4th grade · Math · Unit 7 of 17
Equations
Find the mystery number
What your child practices
Solving one-step equations with a box or letter for the unknown, using all four operations, and matching equations to word problems.
New York State Learning Standards learning standard: NY-4.OA.3 · solving multistep word problems with a letter for the unknown
How we explain it
Children can open this short lesson before they practice.
- An equation says two things are equal.
- Use the opposite operation to find the missing number.
- Check by putting your answer back in.
Example: ☐ + 7 = 15. What is ☐? Opposite of adding 7 is subtracting 7. 15 − 7 = 8. Answer: 8
Equations in New York
In the New York State Learning Standards, this is unit 7 of 17 in 4th grade Math, after Patterns & Tables and before Polygons & Perimeter.
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.
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?
÷ 2 = 9
- 11
- 18
- 20
- 16
18
Hint: Work backwards with multiplication: if a number shared into 2 groups gives 9, the number is 9 × 2 = 18.
Question 2
What number goes in the box?
− 527 = 123
answer box
650
Hint: Work backwards: you took away 527 and had 123 left. Add 527 back on to 123.
Question 3
What number makes both sides equal?
3 × 3 = + 5
answer box
4
Hint: The = sign means both sides are worth the same. The left side is 3 × 3 = 9. What plus 5 makes 9?
Question 4
What number goes in the box?
× 7 = 42
answer box
6
Hint: What times 7 makes 42? Divide to find it: 42 ÷ 7.
Question 5
Some grapes were shared equally by 5 friends. Each friend got 9 grapes. How many grapes were there?
🍇answer box
45
Hint: Write it as an equation: ☐ ÷ 5 = 9. Multiply to work backwards.
Question 6
What number goes in the box?
221 + = 409
answer box
188
Hint: What do you add to 221 to make 409? Subtract to find it: 409 − 221.