Lesson 5

Earning Money

Est. Class Sessions: 2

Daily Practice and Problems

Teacher Notes
X

TIMS Bit

  1. Possible response: One of the subtraction problems will have the smallest answer. The answer for Question 2 will be a little less than 500 because 262 is close to 250 and 750 − 250 = 500. Question 5 will have the smallest answer because 8997 is almost 9000, so the answer will be around 145. Discuss students' predictions and strategies for finding the smallest answer before solving the problems.
  2. 488
  3. 1540
  4. 346
  5. 148
  6. Possible strategy: Counting back:
    9145 − 145 = 9000
    9000 − 3 = 8997
    145 + 3 = 148

O. Addition and Subtraction Practice

Complete these problems using pencil and paper or mental math. Use the Addition Strategies Menu and the Subtraction Strategies Menu from the Student Guide Reference section.

  1. Predict which of the following problems will have the smallest answer (sum or difference). Explain how you know.
  1.    750
    − 262
  2.    689
    + 851
  3.    148
    + 198
  4.    9145
    − 8997
  1. Explain how you can solve Question 5 using mental math.