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3rd grade · Math · Unit 5 of 14

Patterns & Equations

Pattern rules and mystery numbers

What your child practices

Extending increasing and decreasing patterns, describing pattern rules in words and tables, and solving one-step equations like ☐ + 8 = 23.

Alaska content standards learning standard: 3.OA.4; 3.OA.9 · finding unknown numbers in equations and explaining arithmetic patterns

How we explain it

Children can open this short lesson before they practice.

  1. An equation has an = sign. Both sides are the same.
  2. A letter or box stands for a missing number.
  3. Do the opposite to find it: the opposite of + is −.

Example: n + 7 = 15 Undo + 7 by taking away 7. 15 − 7 = 8. Answer: n = 8

Patterns & Equations in Alaska

In the Alaska content standards, this is unit 5 of 14 in 3rd grade Math, after Fractions and before Measuring.

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: Alaska Department of Education and Early Development

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 number goes in the box?

    + 18 = 81

    answer box

  2. Question 2

    What number comes next?

    39, 36, 33, 30,

    • 24
    • 26
    • 28
    • 27

  3. Question 3

    Which pattern rule fits?

    210, 310, 410, 510

    • Start at 210 and add 100 each time
    • Start at 310 and add 100 each time
    • Start at 210 and subtract 100 each time
    • Start at 210 and add 200 each time

  4. Question 4

    Which equation matches the story? The is the number we don't know.

    Sofia had 96 beads.

    Sofia gave some to friends.

    Now Sofia has 18.

    • 96 − ☐ = 18
    • ☐ − 96 = 18
    • 96 + 18 = ☐

  5. Question 5

    What number is missing from the pattern?

    118, 218, 318, , 518

    answer box

  6. Question 6

    What number goes in the box?

    − 47 = 36

    • 82
    • 84
    • 83
    • 93

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