# ALEX Resources

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ALEX Classroom Resources
Subject: Mathematics (2)
Title: Grade 2 Mathematics Module 3, Topic G
Description:

Topic G closes Module 3 with questions such as, “What number is 10 less than 402?” and “What number is 100 more than 98?” As students have been counting up and down throughout the module, these three lessons should flow nicely out of their work thus far and provide a valuable transition to the addition and subtraction of the coming module where more and less will be re-interpreted as addition and subtraction of one, ten, and a hundred (2.NBT.8). The language component of this segment is essential, too. Students need to be encouraged to use their words to make statements such as, “452 is 10 less than 462 and 100 less than 562.” This allows for a greater understanding of comparison word problems (2.0A.1) wherein the language of more and less is a constant presence.

Subject: Mathematics (2)
Title: Grade 2 Mathematics Module 4, Topic A
Description:

In Module 4, Topic A, students build upon their understanding of the base ten system and their prior knowledge of place value strategies presented in Module 3. In Lesson 1, students relate 10 more and 10 less and 1 more and 1 less to addition and subtraction. They recognize that they must add and subtract like units and that the digit in the tens place changes when adding and subtracting 10, just as the digit in the ones place changes when adding or subtracting 1. Students see numbers in terms of place value units; 54 – 10 is 5 tens 4 ones minus 1 ten. They learn to record the addition and subtraction of multiples of 10 using arrow notation. In Lesson 2, students apply place value understanding to add and subtract multiples of 10 before counting on by tens. For example, when adding 20 to 43, they may count 53, 63. Students also develop flexibility in using related addition problems. For example, to solve 92 – 60, one student might think 9 tens – 6 tens is 3 tens, plus 2 is 32, while another starts at 60, adds on 3 tens, and then 2 ones to reach 92, so 32.

Subject: Mathematics (2)
Title: Grade 2 Mathematics Module 4, Topic D