Lesson 2.3: Subtraction of Whole Numbers & Decimals

Objective: To apply the trade-first and partial-differences methods for subtraction.

Key Concepts:· explore algorithms for multi-digit subtraction problems· Make magnitude estimates for subtraction· identify, write, and solve number sentences that model subtraction number stories

October 12th and 13th

1. Go over HW2. Lesson 2.33. Target Practice Game4. HW: SL 2.3 & subtraction practice

2.3Everyday Math

Math Starter

0.654 + 0.872

TLG Page 81Getting Started

Solve using the partial sums algorithm

2.3Everyday Math

Math Starter

TLG Page 81Getting Started

Solve using any method you want!

658+ 729

2.3Everyday Math

Math Starter Answers

TLG Page 81Getting Started

658+ 7290.654 + 0.872

2.3Everyday Math

1 3 57 9 11 Math Message

TLG Page 92Getting Started

Solve each problem.

81 - 47 = ? 8.1 - 4.7 = ?

Describe how the two problems are alike and different.

Follow along with this example on page 15 in your SRB.

Trade First Example Problems

Follow along on page 17 of your SRB

Follow along on page 17 of your SRB

2.3Everyday Math

TLG p. 94Part 1

Partial-Difference MethodReviewing the

The subtraction is performed left to right, column by column.

To find the final answer, the partial differences are added or subtracted.

If the bottom number is less than the top number, then the result will be added to obtain the final answer.

If the bottom number is greater than the top number , then the result will be subtracted to obtain the final answer.

The smaller number in each column is always subtracted from the larger number.

2.3Everyday Math

TLG P. 95Part 1

Math Journal

Open your journal to page 35 and complete the problems as instructed in the directions.

Remember to use the workspace provided.

TLG P. 95Part 1

TLG P. 95Part 1

TLG P. 95Part 2

page

331

in

your

SRB

Subtraction Target Practice

TLG P. 95Part 1

Math Journal- Complete Math Boxes 1-4