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5th grade · Math · Unit 7 of 12

Mental Math Tricks

Facts to 81 and clever shortcuts

What your child practices

Recalling multiplication and division facts to 9 × 9, and mental strategies such as adding zeros, halving and doubling, and breaking a number into friendly parts.

Minnesota K-12 Academic Standards benchmark: 5.3.5.7; 5.3.5.1 · multiplying by powers of 10 and mental multiplication strategies

How we explain it

Children can open this short lesson before they practice.

  1. Use facts you know to find ones you do not: 6 × 8 is double 3 × 8.
  2. Break a number apart: 7 × 12 = 7 × 10 + 7 × 2.
  3. Doubling and halving can make a product easier.

Example: Use a trick: 9 × 7 = ? 9 × 7 is 10 × 7 minus one 7. 70 − 7 = 63. Answer: 63

Mental Math Tricks in Minnesota

In the Minnesota K-12 Academic Standards, this is unit 7 of 12 in 5th grade Math, after Patterns & Equations and before Parentheses & Expressions.

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: Minnesota Department of Education (MDE)

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

    6 × 40 = ?

    • 24
    • 240
    • 2,400

  2. Question 2

    6 × 7 = ?

    • 36
    • 48
    • 42

  3. Question 3

    63 ÷ 7 = ?

    • 9
    • 7
    • 8

  4. Question 4

    Half of 46 is 23. So 4 × 23 is the same as…

    • 4 × 46
    • 2 × 46
    • 2 × 23

  5. Question 5

    3 × 6 = 18. What is 300 × 6?

    • 1,800
    • 18,000
    • 180

  6. Question 6

    3,600 ÷ 9 = ?

    • 4,000
    • 400
    • 40

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