What is this unit all about?

The focus of this unit is on addition and subtraction within 1000. Students focus on understanding and applying strategies, such as place value blocks, place value drawings, expanded form/method, and numbers lines to add and subtract numbers up to and including 1,000. Students will simultaneously review concepts about place value, regrouping, and ungrouping.

Throughout the unit, students will use these operations within the context of one and two step story problems. They will also develop an understanding of how place value can then be used to round numbers.

The primary strategy used for rounding in this unit is the number line. Students will use the number line to round numbers to the nearest ten and hundred. Rounding and other estimating strategies, such as benchmarking, will help students have a better understanding of the reasonableness of their final answers when finding a solution to a math problem.

Students will also be asked to explain their math thinking, make sense of the strategies they used, and assess the reasonableness of their answers.

North Carolina State Standards:

NC.3.NBT.2- Add and subtract whole numbers up to and including 1,000.

• Use estimation strategies to assess reasonableness of answers.

• Model and explain how the relationship between addition and subtraction can be applied to solve addition and subtraction problems.

• Use expanded form to decompose numbers and then find sums and differences.

NC.3.OA.8- Solve two-step word problems involving addition, subtraction, and multiplication, representing problems using equations with a symbol for the unknown number.

At the end of the unit, students will be able to:

• Use expanded form to decompose numbers to solve addition and subtraction problems

• Apply the relationship between addition and subtraction to solve problems

• Solve two-step word problems using addition and subtraction

Addition Videos:

Subtraction Videos:

Essential Vocabulary

Unit 3 Student handouts