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.
Arizona Academic Standards learning standard: 3.OA.A.4; 3.OA.D.9 · finding unknown numbers in equations and explaining arithmetic patterns
How we explain it
Children can open this short lesson before they practice.
- An equation has an = sign. Both sides are the same.
- A letter or box stands for a missing number.
- 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 Arizona
In the Arizona Academic 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: 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.
Question 1
What number goes in the box?
+ 56 = 89
answer box
33
Hint: What number plus 56 makes 89? Think 89 − 56 = 33.
Question 2
What number goes in the box?
50 + = 72
- 122
- 22
- 23
- 21
22
Hint: Count up from 50 to 72, or think 72 − 50 = 22.
Question 3
What number goes in the box?
62 − = 28
- 35
- 90
- 34
- 33
34
Hint: What do you take away from 62 to leave 28? Count up from 28 to 62: 34.
Question 4
Which pattern rule fits?
622, 522, 422, 322
- Start at 522 and subtract 100 each time
- Start at 622 and subtract 100 each time
- Start at 622 and add 100 each time
- Start at 622 and subtract 200 each time
Start at 622 and subtract 100 each time
Hint: The pattern starts at 622. Then it changes by the same amount each time: 622 to 522 is −100.
Question 5
Follow the pattern. What number goes where the ? is?
Cars Wheels 1 4 2 8 3 12 4 16 5 ? answer box
20
Hint: Each row has 4 more wheels. Keep adding 4: 16 → 20.
Question 6
What number is missing from the pattern?
0, 25, , 75, 100
answer box
50
Hint: The numbers go up by 25 each time. 25 + 25 = 50.