Lesson 6

Using Estimation

Est. Class Sessions: 2–3

Daily Practice and Problems

Teacher Notes
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TIMS Task

  1. Responses will vary. In the first three strategies, the partial products 100 and 35 are added to get the answer. Larry and Curly both partitioned 27 into tens and ones. Moe multiplied the 2 tens and 7 ones separately, but he didn’t write the partition out. Larry showed the partition using a rectangle and Curly showed it using expanded form. Joe used mental math by doubling 5 to get 10. Then he multiplied 27 × 10 = 270. Then he halved 270 to get 135.

V. Larry, Curly, Moe, and Joe

Larry, Curly, Moe, and Joe solved 27 × 5 in four different ways.



  1. How are their four strategies alike? How are they different?
  2. Show how to solve 64 × 5 using all four methods.