Unit 1

Sums and Differences to 20

Grade 2


Description: In grade 2, students review and extend addition and subtraction strategies that will help them practice and increase fluency in adding and subtracting within 20. Students learn to represent and solve word problems using addition and subtraction.

Louisiana Student Standards for Mathematics (LSSM)

Instructional Outcomes

OA - Operations and Algebraic Thinking

Represent and solve problems involving addition and subtraction.




Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.

Add and subtract within 20.




Fluently add and subtract within 20 using mental strategies.  By end of Grade 2, know from memory all sums of two one-digit numbers.

NBT – Number and Operation in Base Ten

Use place value understanding and properties of operations to add and subtract.




Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.


Enduring Understandings:


·         Numbers help to answer everyday questions, such as, “how many” and “how much”.

·         Numbers can be thought about and used in different ways.

·         Numbers can be shown in all kinds of ways.

·         There is more than one way to solve a problem.

·         Addition and subtraction are related operations.

·         Numbers can be composed and decomposed.

·         Knowing basic facts helps to solve other problems efficiently.

Essential Questions:


·         What are different ways we can show or make (represent) a number?

·         Why do I use numbers to show “how much” and “how many”?

·         How can I solve the same problem in more than one way?

·         How are addition and subtraction opposite operations?

·         How can I compose and decompose a number?

·         How can I use the basic facts to solve other problems?