Lesson 7

A Different Sieve

Est. Class Sessions: 2

Daily Practice and Problems

Teacher Notes
X

TIMS Task

Have the Multiplication and Division Facts chart readily available.

    1. 1, 23; prime
    2. 1, 2, 3, 6, 43, 86, 129, 258
    3. 1, 3, 13, 39
    4. 1, 73; prime
    5. 1, 2, 3, 6, 9, 18, 71, 142, 213, 426, 639, 1278
    1. prime
    2. 2 × 3 × 43
    3. 3 × 13
    4. prime
    5. 2 × 32 × 71

Ongoing Assessment

Use Task V to assess students' abilities to identify and categorize prime, composite, and square numbers [E1]; find factors of a number [E5]; and find the prime factorization of a number [E6].

V. Finding Factors

  1. Find all the factors for the following numbers. Tell which numbers are prime.
    1. 23
    2. 258
    3. 39
    4. 73
    5. 1278
  2. Draw a factor tree for each composite number above. Then write its prime factorization.