Lesson 2

Sifting for Primes

Est. Class Sessions: 1–2

Daily Practice and Problems

Teacher Notes
X

TIMS Task

Discuss students' estimation strategies.

    1. 7874
    2. 78.74
    3. .07874
    1. 329 R6
    2. 342 R6
    3. 944
  3. Possible strategy:

    2309 is close to 2100.
    2100 ÷ 7 = 300.
    The answer will be more than 300.

F. Practice

Solve the following problems using paper and pencil or mental math. Use a separate sheet of paper. Estimate to be sure your answers are reasonable. Use the Multidigit Multiplication Strategies Menu and the Division Strategies Menu in the Student Guide Reference section.

  1. A. 127 × 62 =

    B. 12.7 × 6.2 =

    C. .127 × .62 =
  2. A. 2309 ÷ 7 =

    B. 2400 ÷ 7 =

    C. 6608 ÷ 7 =
  1. Explain your estimation strategy for Question 2A.