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Example

Solving a Two-Step Number Problem Using "Sum" and "Twice"

Apply the seven-step problem-solving strategy to a number problem whose translation involves two operations — multiplication and addition — producing a two-step equation.

Problem: The sum of twice a number and seven is 1515. Find the number.

  1. Read the problem and confirm understanding of all terms.
  2. Identify what to find: the number.
  3. Name the unknown: Let nn = the number.
  4. Translate by recognizing two keywords: twice signals multiplication by 22, and sum signals addition. Restate the problem as "The sum of twice nn and 77 is 1515," which converts to:

2n+7=152n + 7 = 15

  1. Solve using two inverse operations. First, subtract 77 from both sides:

2n+77=1572n + 7 - 7 = 15 - 7

2n=82n = 8

Then divide both sides by 22:

2n2=82\frac{2n}{2} = \frac{8}{2}

n=4n = 4

  1. Check: Is the sum of twice 44 and 77 equal to 1515?

24+7=?152 \cdot 4 + 7 \stackrel{?}{=} 15

15=1515 = 15 \checkmark

  1. Answer: The number is 44.

Unlike one-step number problems where a single keyword produces a single-operation equation, this problem combines two keywords ("twice" and "sum") to generate 2n+7=152n + 7 = 15, which requires both subtraction and division to solve. As comfort grows, intermediate steps may be condensed — but writing out every step is perfectly fine while building confidence.

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Updated 2026-04-21

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