Variable as Placeholder Math Example 3

Follow the full solution, then compare it with the other examples linked below.

Example 3

medium
Maria has some stickers. After giving away 8, she has 15 left. Write an equation and find how many she started with.

Solution

  1. 1
    Step 1: Let ss be the number of stickers Maria started with (the unknown placeholder).
  2. 2
    Step 2: Write the equation: s−8=15s - 8 = 15.
  3. 3
    Step 3: Add 8 to both sides: s=15+8=23s = 15 + 8 = 23.
  4. 4
    Check: 23−8=1523 - 8 = 15 ✓

Answer

s=23s = 23
The variable ss is a placeholder for the single unknown quantity — the original number of stickers. Translating the word problem into an equation lets us solve for the specific value.

About Variable as Placeholder

A variable acts as a placeholder — a letter or symbol (like x, n, or y) that stands in for an unknown or changing number in a mathematical expression or equation. It represents one specific unknown value that satisfies a given condition.

Learn more about Variable as Placeholder →

More Variable as Placeholder Examples

Example 1 easy

In the equation [formula], what specific value does [formula] represent?

Example 2 medium

A rectangle has area 24 cm² and width 4 cm. Use a variable to find the length.

Example 4 easy

Find the value of [formula] in [formula].

Example 5 medium

I think of a number, double it, and add 5 to get 19. What is my number?

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