Worked Example 1
Unknown Factor
4 packs hold 96 stickers in all. How many stickers are in each pack?
- 1Equation: 4 × n = 96.
- 2Think: what times 4 is 96? Use division: 96 ÷ 4 = 24.
- 3Check: 4 × 24 = 96.
Answer: n = 24
Florida Grade 5 Math · Algebraic Reasoning
MA.5.AR.2.4: Writing equations with an unknown
What this Grade 5 benchmark means, worked examples, common mistakes, and a free printable worksheet.
Created by a Florida mom · Published by Tropical Learning LLC
What Is Benchmark MA.5.AR.2.4?
In Grade 5, students write an equation for a math or real-world situation, using a letter or symbol for the unknown number, and then find it. The unknown can be in any position.
For example, "4 packs hold 96 stickers in all" becomes 4 × n = 96, and "Lee had 85 cards, gave some away, and has 37 left" becomes 85 − n = 37.
Official benchmarkGiven a mathematical or real-world context, write an equation involving any of the four operations to determine the unknown whole number with the unknown in any position.
On the FAST test: part of the Grade 5 reporting category Algebraic Reasoning, which is about 23–29% of the test.
Worked Examples
Worked Example 2
Unknown Amount Subtracted
Lee had 85 cards, gave some away, and has 37 left. How many did he give away?
- 1Equation: 85 − n = 37.
- 2Find the difference: 85 − 37 = 48.
- 3Check: 85 − 48 = 37.
Answer: n = 48
Common Mistakes to Watch For
Using the wrong operation to find the unknown
Wrong:120 ÷ n = 8, so n = 960
If 120 divided by a number is 8, the number is 120 ÷ 8 = 15. Check: 120 ÷ 15 = 8.
Writing the equation in the wrong order
Wrong:Lee: n − 85 = 37
Lee started with 85, so the equation starts with 85: 85 − n = 37.
Helpful Math Tip
Always check by putting your answer back into the equation. If both sides match, the answer is right.
Related Grade 5 Skills
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