Chapter 3: Add and Subtract Whole Numbers

Lesson 1: Use Mental Math Strategies. Objective: To use mental math strategies to find sums and differences.

Lesson 2: Estimate Sums and Differences. Objective: To estimate sums and differences.

Lesson 3: Add and Subtract to 4-Digit Numbers. Objective: To add and subtract to 4-digit numbers.

Lesson 4: Subtract Across Zeros. Objective: To subtract whole numbers with zero and regrouping.

Lesson 5: Choose a Method. Objective: To add and subtract numbers with regrouping through hundred thousands.

Lesson 6: Problem Solving Strategy: Estimate or Find Exact Answers. Objective: To solve problems by deciding whether to estimate or find exact answers.

Vocabulary: sum, difference, estimate, round

**sum:** the answer to an addition problem

**difference:** the answer to a subtraction problem

**estimate: **to find an answer close to an exact answer

**round:** to replace a number with another number that tells about how many or how much

Rounding Help:

**Rounding Rap**

Mark the place. Look to the right. 4 or less are out of sight. 5 and up will buy one more before they too are out the door. In those empty right-hand spaces, zeros keep the proper places.

Estimating and rounding:

http://www.math.com/school/subject1/lessons/S1U1L3GL.html

Rounding Whole Numbers: http://www.basic-mathematics.com/rounding-whole-numbers.html

Our textbook website: www.harcourtschool.com

Some good practice websites:

http://www.gamequarium.com/placevalue.html

http://www.softschools.com/math/games/

www.multiplication.com

www.funbrain.com