Lesson 5

Paper-and-Pencil Subtraction:
Expanded Form

Est. Class Sessions: 2–3

Daily Practice and Problems

Teacher Notes
X
  1. Possible response: John could have used a 200 Chart starting on 72 moving 8 spaces to the end of the row at 80, then 2 rows, or 20, down to 80 to get to 100, then 5 more rows down, or 50, to 150. Then he added
    8 + 20 + 50 = 78.

  2. Possible response: I thought of money. 72¢ is close to 75¢, so I skip counted by quarters to $1.50: 75, 100, 125, 150 or three quarters. Three quarters is 75¢, then I added the 3¢ extra, 75¢ + 3¢ = 78¢.

R. How Did He Do It

John shows how he solves $1.50 − $0.72.

72 to 80 is 8

80 to 100 is 20

100 to 150 is 50

answer 78¢

  1. Show or tell how John solved the problem.


  2. Show another way to solve this problem.