Lesson 3

Tangram Puzzles

Est. Class Sessions: 2

Daily Practice and Problems

Teacher Notes
X

TIMS Task

  1. 369
  2. 4397
  3. 52
  4. 403
  1. Possible response: I rounded 602 back 2 to 600 and 199 up 1 to 200 and then subtracted 600 − 200 = 400. Then I added 3 to my answer. The 3 came from the two I took off the 602 and the one I added to the 199 when I rounded.
  3. Possible response: I used convenient numbers to estimate 230 − 180 = 50. My estimate of 50 is very close to 52, so I know my answer is reasonable.

H. Subtraction

Choose a strategy from the Subtraction Strategies Menu in the Student Guide Reference section to solve the following problems.

  1. Show how to use mental math or a number line to solve Question 4.
  2. Show how to use addition to check your answer for Question 2.
  3. Show or tell how you know your answer for Question 3 is reasonable.