[MA2019] (2) 20 :
20. Measure to determine how much longer one object is than another, expressing the length difference of the two objects using standard units of length. [MA2019] (2) 21 :
21. Use addition and subtraction within 100 to solve word problems involving same units of length, representing the problem with drawings (such as drawings of rulers) and/or equations with a symbol for the unknown number.