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6th grade · Math · Unit 1 of 17

Facts & Factors

Facts, primes, GCF and LCM

What your child practices

Quick recall of multiplication and division facts, plus factors, multiples and prime numbers, the greatest common factor (GCF) and least common multiple (LCM), and word problems that use them.

Arizona Academic Standards learning standard: 6.NS.B.4 · greatest common factor and least common multiple

How we explain it

Children can open this short lesson before they practice.

  1. A factor divides a number evenly. 3 and 4 are factors of 12.
  2. The greatest common factor (GCF) is the biggest factor two numbers share.
  3. The least common multiple (LCM) is the smallest multiple they share.

Example: Find the GCF of 12 and 18. Factors of 12: 1, 2, 3, 4, 6, 12. Factors of 18: 1, 2, 3, 6, 9, 18. The biggest shared one is 6. Answer: 6

Facts & Factors in Arizona

In the Arizona Academic Standards, this is unit 1 of 17 in 6th grade Math, before Mixed Numbers & Ratios.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Arizona Department of Education

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    What is 64 ÷ 8?

    64 ÷ 8 = ?

    answer box

  2. Question 2

    Which of these numbers is prime?

    • 57
    • 21
    • 39
    • 41

  3. Question 3

    What is 6 × 8?

    6 × 8 = ?

    answer box

  4. Question 4

    Which number is a multiple of 6?

    • 57
    • 53
    • 54
    • 55

  5. Question 5

    What number goes in the box?

    4 × = 12

    • 3
    • 1
    • 2
    • 5

  6. Question 6

    Two lights blink together. One blinks every 8 seconds and the other every 6 seconds. After how many seconds will they next blink at the same time?

    • 24
    • 8
    • 48
    • 14

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