Addition and Subtraction StrategiesUnit of Study: Building Fluency with Addition and SubtactionGlobal Concept Guide: 1 of 2

Content DevelopmentIt is no accident that the standard says “know from memory” rather than “memorize”. The standards are NOT dictating timed tests.

Day 1 Model for students how to use an open number line to add and

subtract more fluently. Then pose scenarios that model addition and subtraction

sentences on an open number line to help students think flexibly.

Day 2 The purpose of this day is for students to understand the

inverse relationship between addition and subtraction to help them build their fact fluency.

In the lesson ideas section of the GCG you can use the Fact Family Houses link as a tool to use with students.

Day 3/4 Understanding place value is a fundamental skill for students to

be proficient at if they are to understand addition and subtraction as well as be fluent with their facts.

Use a lot of base ten models on this day to represent addition and subtraction scenarios with regrouping.

Example: 37 + 19 can be represented as 30 + 10 and 7 + 9 + =40 and + = 16

40 + 16 = 56

Day 5 On this day the focus is on using a part-part-whole mat to

determine what the question is asking and assist students in thinking through the problem.

Use the part-part-whole questions under lesson ideas to guide your instruction.

Enrich/Reteach/Intervention

Reteach-Pull small groups of students and give them more exposure to the strategies. Manipulatives should be used to reinforce these addition and subtraction strategies.

Pose problems for students and encourage them to use mental math to solve the math using the strategies that have been covered in this GCG.