# Courses of Study : Mathematics

Number of Standards matching query: 41
Number and Quantity
Together, irrational numbers and rational numbers complete the real number system, representing all points on the number line, while there exist numbers beyond the real numbers called complex numbers.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
1. Explain how the meaning of rational exponents follows from extending the properties of integer exponents to those values, allowing for an additional notation for radicals using rational exponents.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.1 Determine the value of a quantity that is squared or cubed (limited to perfect squares and perfect cubes).

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
2. Rewrite expressions involving radicals and rational exponents using the properties of exponents.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.1 Determine the value of a quantity that is squared or cubed (limited to perfect squares and perfect cubes).

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
3. Define the imaginary number i such that i2 = -1.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.1 Determine the value of a quantity that is squared or cubed (limited to perfect squares and perfect cubes).

Algebra and Functions
Focus 1: Algebra
Expressions can be rewritten in equivalent forms by using algebraic properties, including properties of addition, multiplication, and exponentiation, to make different characteristics or features visible.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 7 Learning Activities: 2 Classroom Resources: 5
4. Interpret linear, quadratic, and exponential expressions in terms of a context by viewing one or more of their parts as a single entity.

Example: Interpret the accrued amount of investment P(1 + r)t , where P is the principal and r is the interest rate, as the product of P and a factor depending on time t.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.4 Identify an algebraic expression involving addition or subtraction to represent a real-world problem.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 13 Learning Activities: 1 Classroom Resources: 12
5. Use the structure of an expression to identify ways to rewrite it.

Example: See x4 - y4 as (x2)2 - (y2)2, thus recognizing it as a difference of squares that can be factored as (x2 - y2)(x2 + y2).

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.5 Solve simple algebraic equations using real-world scenarios with one variable using multiplication or division.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 12 Learning Activities: 1 Classroom Resources: 11
6. Choose and produce an equivalent form of an expression to reveal and explain properties of the quantity represented by the expression.

a. Factor quadratic expressions with leading coefficients of one, and use the factored form to reveal the zeros of the function it defines.

b. Use the vertex form of a quadratic expression to reveal the maximum or minimum value and the axis of symmetry of the function it defines; complete the square to find the vertex form of quadratics with a leading coefficient of one.

c. Use the properties of exponents to transform expressions for exponential functions.

Example: Identify percent rate of change in functions such as y = (1.02)t, y = (0.97)t, y = (1.01)12t, y = (1.2)t/10, and classify them as representing exponential growth or decay.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.5 Solve simple algebraic equations using real-world scenarios with one variable using multiplication or division.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 14 Learning Activities: 5 Classroom Resources: 9
7. Add, subtract, and multiply polynomials, showing that polynomials form a system analogous to the integers, namely, they are closed under the operations of addition, subtraction, and multiplication.
Finding solutions to an equation, inequality, or system of equations or inequalities requires the checking of candidate solutions, whether generated analytically or graphically, to ensure that solutions are found and that those found are not extraneous.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
8. Explain why extraneous solutions to an equation involving absolute values may arise and how to check to be sure that a candidate solution satisfies an equation.

The structure of an equation or inequality (including, but not limited to, one-variable linear and quadratic equations, inequalities, and systems of linear equations in two variables) can be purposefully analyzed (with and without technology) to determine an efficient strategy to find a solution, if one exists, and then to justify the solution.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 21 Learning Activities: 2 Classroom Resources: 19
9. Select an appropriate method to solve a quadratic equation in one variable.

a. Use the method of completing the square to transform any quadratic equation in x into an equation of the form (x - p)2 = q that has the same solutions. Explain how the quadratic formula is derived from this form.

b. Solve quadratic equations by inspection (such as x2 = 49), taking square roots, completing the square, the quadratic formula, and factoring, as appropriate to the initial form of the equation, and recognize that some solutions may not be real.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.9 Identify equivalent expressions given a linear expression using arithmetic operations.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 9 Classroom Resources: 9
10. Select an appropriate method to solve a system of two linear equations in two variables.

a. Solve a system of two equations in two variables by using linear combinations; contrast situations in which use of linear combinations is more efficient with those in which substitution is more efficient.

b. Contrast solutions to a system of two linear equations in two variables produced by algebraic methods with graphical and tabular methods.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.9 Identify equivalent expressions given a linear expression using arithmetic operations.

Expressions, equations, and inequalities can be used to analyze and make predictions, both within mathematics and as mathematics is applied in different contexts - in particular, contexts that arise in relation to linear, quadratic, and exponential situations.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 6 Classroom Resources: 6
11. Create equations and inequalities in one variable and use them to solve problems in context, either exactly or approximately. Extend from contexts arising from linear functions to those involving quadratic, exponential, and absolute value functions.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.11 Select an equation or inequality involving one operation (limit to addition or subtraction) with one variable that represents a real-world problem. Solve the equation.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 3 Classroom Resources: 3
12. Create equations in two or more variables to represent relationships between quantities in context; graph equations on coordinate axes with labels and scales and use them to make predictions. Limit to contexts arising from linear, quadratic, exponential, absolute value, and linear piecewise functions.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.11 Select an equation or inequality involving one operation (limit to addition or subtraction) with one variable that represents a real-world problem. Solve the equation.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
13. Represent constraints by equations and/or inequalities, and solve systems of equations and/or inequalities, interpreting solutions as viable or nonviable options in a modeling context. Limit to contexts arising from linear, quadratic, exponential, absolute value, and linear piecewise functions.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.11 Select an equation or inequality involving one operation (limit to addition or subtraction) with one variable that represents a real-world problem. Solve the equation.

Focus 2: Connecting Algebra to Functions
Functions shift the emphasis from a point- by-point relationship between two variables (input/output) to considering an entire set of ordered pairs (where each first element is paired with exactly one second element) as an entity with its own features and characteristics.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
14. Given a relation defined by an equation in two variables, identify the graph of the relation as the set of all its solutions plotted in the coordinate plane.
Note: The graph of a relation often forms a curve (which could be a line).

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.14 When given a relation in table form, identify the graph that represents the relation. (Ex: The points (5,5); (6,4); (3,7) are given to the student along with three graphs, and the student chooses the graph that represents the relation.)

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 5 Learning Activities: 1 Classroom Resources: 4
15. Define a function as a mapping from one set (called the domain) to another set (called the range) that assigns to each element of the domain exactly one element of the range.

a. Use function notation, evaluate functions for inputs in their domains, and interpret statements that use function notation in terms of a context. Note: If f is a function and x is an element of its domain, then f(x) denotes the output of f corresponding to the input x.

b. Relate the domain of a function to its graph and, where applicable, to the quantitative relationship it describes. Limit to linear, quadratic, exponential, and absolute value functions.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.15 Use the vertical line test to determine if a given relation is a function.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 3 Classroom Resources: 3
16. Compare and contrast relations and functions represented by equations, graphs, or tables that show related values; determine whether a relation is a function. Explain that a function f is a special kind of relation defined by the equation y = f(x).

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.15 Use the vertical line test to determine if a given relation is a function.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 8 Lesson Plans: 2 Classroom Resources: 6
17. Combine different types of standard functions to write, evaluate, and interpret functions in context. Limit to linear, quadratic, exponential, and absolute value functions.

a. Use arithmetic operations to combine different types of standard functions to write and evaluate functions.

Example: Given two functions, one representing flow rate of water and the other representing evaporation of that water, combine the two functions to determine the amount of water in a container at a given time.

b. Use function composition to combine different types of standard functions to write and evaluate functions.

Example: Given the following relationships, determine what the expression S(T(t)) represents.

Function Input Output
G Amount of studying: s Grade in course: G(s)
S Grade in course: g Amount of screen time: S(g)
T Amount of screen time: t Number of follers: T(t)
Graphs can be used to obtain exact or approximate solutions of equations, inequalities, and systems of equations and inequalities - including systems of linear equations in two variables and systems of linear and quadratic equations (given or obtained by using technology).
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
18. Solve systems consisting of linear and/or quadratic equations in two variables graphically, using technology where appropriate.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.18 Interpret the meaning of a point on the graph of a line. (Ex.: On a graph of football ticket purchases, trace the graph to a point and tell the number of tickets purchased and the total cost.)

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
19. Explain why the x-coordinates of the points where the graphs of the equations y = f(x) and y = g(x) intersect are the solutions of the equation f(x) = g(x).

a. Find the approximate solutions of an equation graphically, using tables of values, or finding successive approximations, using technology where appropriate.
Note: Include cases where f(x) is a linear, quadratic, exponential, or absolute value function and g(x) is constant or linear.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.18 Interpret the meaning of a point on the graph of a line. (Ex.: On a graph of football ticket purchases, trace the graph to a point and tell the number of tickets purchased and the total cost.)

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
20. Graph the solutions to a linear inequality in two variables as a half-plane (excluding the boundary in the case of a strict inequality), and graph the solution set to a system of linear inequalities in two variables as the intersection of the corresponding half-planes, using technology where appropriate.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.18 Interpret the meaning of a point on the graph of a line. (Ex.: On a graph of football ticket purchases, trace the graph to a point and tell the number of tickets purchased and the total cost.)

Focus 3: Functions
Functions can be described by using a variety of representations: mapping diagrams, function notation (e.g., f(x) = x2), recursive definitions, tables, and graphs.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 3 Classroom Resources: 3
21. Compare properties of two functions, each represented in a different way (algebraically, graphically, numerically in tables, or by verbal descriptions). Extend from linear to quadratic, exponential, absolute value, and general piecewise.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.21 Given a function table, identify the missing number.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
22. Define sequences as functions, including recursive definitions, whose domain is a subset of the integers.

a. Write explicit and recursive formulas for arithmetic and geometric sequences and connect them to linear and exponential functions.

Example: A sequence with constant growth will be a linear function, while a sequence with proportional growth will be an exponential function.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.22 Given a sequence of numbers, identify the rule that will give you the next number in the sequence. [Limit to expressions with simple arithmetic (adding or subtracting) or geometric (multiplying or dividing) operations.]

Functions that are members of the same family have distinguishing attributes (structure) common to all functions within that family.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 4 Learning Activities: 1 Classroom Resources: 3
23. Identify the effect on the graph of replacing f(x) by f(x)+k,k·f(x), f(k·x), and f(x+k) for specific values of k (both positive and negative); find the value of k given the graphs. Experiment with cases and explain the effects on the graph, using technology as appropriate. Limit to linear, quadratic, exponential, absolute value, and linear piecewise functions.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.24 Given a simple linear function on a graph, select the model that represents an increase by equal amounts over equal intervals.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 4 Learning Activities: 3 Classroom Resources: 1
24. Distinguish between situations that can be modeled with linear functions and those that can be modeled with exponential functions.

a. Show that linear functions grow by equal differences over equal intervals, while exponential functions grow by equal factors over equal intervals.

b. Define linear functions to represent situations in which one quantity changes at a constant rate per unit interval relative to another.

c. Define exponential functions to represent situations in which a quantity grows or decays by a constant percent rate per unit interval relative to another.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.24 Given a simple linear function on a graph, select the model that represents an increase by equal amounts over equal intervals.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 2 Learning Activities: 1 Classroom Resources: 1
25. Construct linear and exponential functions, including arithmetic and geometric sequences, given a graph, a description of a relationship, or two input-output pairs (include reading these from a table).

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.24 Given a simple linear function on a graph, select the model that represents an increase by equal amounts over equal intervals.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
26. Use graphs and tables to show that a quantity increasing exponentially eventually exceeds a quantity increasing linearly or quadratically.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.24 Given a simple linear function on a graph, select the model that represents an increase by equal amounts over equal intervals.

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 2 Learning Activities: 2
27. Interpret the parameters of functions in terms of a context. Extend from linear functions, written in the form mx + b, to exponential functions, written in the form abx.

Example: If the function V(t) = 19885(0.75)t describes the value of a car after it has been owned for t years, 1985 represents the purchase price of the car when t = 0, and 0.75 represents the annual rate at which its value decreases.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.24 Given a simple linear function on a graph, select the model that represents an increase by equal amounts over equal intervals.

Functions can be represented graphically and key features of the graphs, including zeros, intercepts, and, when relevant, rate of change and maximum/minimum values, can be associated with and interpreted in terms of the equivalent symbolic representation.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 3 Classroom Resources: 3
28. For a function that models a relationship between two quantities, interpret key features of graphs and tables in terms of the quantities, and sketch graphs showing key features given a verbal description of the relationship. Note: Key features include: intercepts; intervals where the function is increasing, decreasing, positive, or negative; maximums and minimums; symmetries; and end behavior. Extend from relationships that can be represented by linear functions to quadratic, exponential, absolute value, and linear piecewise functions.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.28 Given graphs that represent linear functions, identify key features (limit to y intercept, x-intercept, increasing, decreasing) and/or interpret different rates of change (e.g., Which is faster or slower?).

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
29. Calculate and interpret the average rate of change of a function (presented symbolically or as a table) over a specified interval. Estimate the rate of change from a graph. Limit to linear, quadratic, exponential, and absolute value functions.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.28 Given graphs that represent linear functions, identify key features (limit to y intercept, x-intercept, increasing, decreasing) and/or interpret different rates of change (e.g., Which is faster or slower?).

 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 12 Learning Activities: 4 Classroom Resources: 8
30. Graph functions expressed symbolically and show key features of the graph, by hand in simple cases and using technology for more complicated cases.

a. Graph linear and quadratic functions and show intercepts, maxima, and minima.

b. Graph piecewise-defined functions, including step functions and absolute value functions.

c. Graph exponential functions, showing intercepts and end behavior.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.30 Given the graph of a linear function, identify the intercepts, the maxima, and minima.

Functions model a wide variety of real situations and can help students understand the processes of making and changing assumptions, assigning variables, and finding solutions to contextual problems.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 0
31. Use the mathematical modeling cycle to solve real-world problems involving linear, quadratic, exponential, absolute value, and linear piecewise functions.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.12.31 Choose the graph of the linear function that represents a solution in a real-world scenario. (Ex: Choose the graph that shows a steady increase or decrease rather than a graph with fluctuating data.)

Data Analysis, Statistics, and Probability
Focus 1: Quantitative Literacy
Mathematical and statistical reasoning about data can be used to evaluate conclusions and assess risks.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
32. Use mathematical and statistical reasoning with bivariate categorical data in order to draw conclusions and assess risk.

Example: In a clinical trial comparing the effectiveness of flu shots A and B, 21 subjects in treatment group A avoided getting the flu while 29 contracted it. In group B, 12 avoided the flu while 13 contracted it. Discuss which flu shot appears to be more effective in reducing the chances of contracting the flu.
Possible answer: Even though more people in group A avoided the flu than in group B, the proportion of people avoiding the flu in group B is greater than the proportion in group A, which suggests that treatment B may be more effective in lowering the risk of getting the flu.

Contracted Flu Did Not Contract Flu
Flu Shot A 29 21
Flu Shot B 13 12
Total 42 32

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.32 Make predictions and draw conclusions from two variable data based on data displays and apply the results to a real-world situation.

Making and defending informed, data- based decisions is a characteristic of a quantitatively literate person.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 0
33. Design and carry out an investigation to determine whether there appears to be an association between two categorical variables, and write a persuasive argument based on the results of the investigation.

Example: Investigate whether there appears to be an association between successfully completing a task in a given length of time and listening to music while attempting the task. Randomly assign some students to listen to music while attempting to complete the task and others to complete the task without listening to music. Discuss whether students should listen to music while studying, based on that analysis.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.33 When given a two-way table summarizing data on two categorical variables collected from the same subjects, identify possible association between the two variables.

Focus 2: Visualizing and Summarizing Data
Data arise from a context and come in two types: quantitative (continuous or discrete) and categorical. Technology can be used to "clean" and organize data, including very large data sets, into a useful and manageable structure?a first step in any analysis of data.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 0
34. Distinguish between quantitative and categorical data and between the techniques that may be used for analyzing data of these two types.

Example: The color of cars is categorical and so is summarized by frequency and proportion for each color category, while the mileage on each car's odometer is quantitative and can be summarized by the mean.
The association between two categorical variables is typically represented by using two-way tables and segmented bar graphs.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 0
35. Analyze the possible association between two categorical variables.

a. Summarize categorical data for two categories in two-way frequency tables and represent using segmented bar graphs.

b. Interpret relative frequencies in the context of categorical data (including joint, marginal, and conditional relative frequencies).

c. Identify possible associations and trends in categorical data.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.35 Interpret general trends on a graph. (Limited to increase and decrease.)

Data analysis techniques can be used to develop models of contextual situations and to generate and evaluate possible solutions to real problems involving those contexts.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 0
36. Generate a two-way categorical table in order to find and evaluate solutions to real-world problems.

a. Aggregate data from several groups to find an overall association between two categorical variables.

b. Recognize and explore situations where the association between two categorical variables is reversed when a third variable is considered (Simpson's Paradox).

Example: In a certain city, Hospital 1 has a higher fatality rate than Hospital 2. But when considering mildly-injured patients and severely-injured patients as separate groups, Hospital 1 has a lower fatality rate among both groups than Hospital 2, since Hospital 1 is a Level 1 Trauma Center. Thus, Hospital 1 receives most of the severely injured patients who are less likely to survive overall but have a better chance of surviving in Hospital 1 than they would in Hospital 2.

Alabama Alternate Achievement Standards
AAS Standard:
M.A.AAS.11.36 When given a real-world scenario, choose the independent or dependent variable. Ex.: If I buy 2 coffees that cost \$2.00 each, the total cost is \$4. Which variable is independent?

Focus 4: Probability
Two events are independent if the occurrence of one event does not affect the probability of the other event. Determining whether two events are independent can be used for finding and understanding probabilities.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 0
37. Describe events as subsets of a sample space (the set of outcomes) using characteristics (or categories) of the outcomes, or as unions, intersections, or complements of other events ("or," "and," "not").
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 0
38. Explain whether two events, A and B, are independent, using two-way tables or tree diagrams.
Conditional probabilities - that is, those probabilities that are "conditioned" by some known information - can be computed from data organized in contingency tables. Conditions or assumptions may affect the computation of a probability.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 1 Classroom Resources: 1
39. Compute the conditional probability of event A given event B, using two-way tables or tree diagrams.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 0
40. Recognize and describe the concepts of conditional probability and independence in everyday situations and explain them using everyday language.

Example: Contrast the chance of having lung cancer if you are a smoker with the chance of being a smoker if you have lung cancer.
 Mathematics (2019) Grade(s): 9 - 12 Algebra I with Probability All Resources: 0
41. Explain why the conditional probability of A given B is the fraction of B's outcomes that also belong to A, and interpret the answer in context.

Example: the probability of drawing a king from a deck of cards, given that it is a face card, is (4/52)/(12/52), which is 1/3.