Rounding to the Nearest Ten

What Is Rounding to the Nearest Ten?

Rounding simplifies numbers by adjusting them to the closest multiple of 10. The ones digit determines the direction: if it is 5 or greater, round up; if less than 5, round down. This skill transforms complex calculations into manageable estimates and is essential for checking whether an exact answer is reasonable.

Why Rounding Matters

Before calculators and smartphones, rounding was how people verified their work. Today, it remains vital for quick estimates in shopping, budgeting, and science. A person who can estimate that 487 + 312 is roughly 500 + 300 = 800 knows immediately that an exact answer of 799 is correct and 7,990 is a decimal error.

The Rounding Rule

Examine the digit in the place to the right of your target. To round to the nearest ten, look at the ones digit. Five or above: increase the tens digit by one and replace ones with zero. Below five: keep the tens digit and replace ones with zero. For 47: ones digit 7 ≥ 5, so 47 → 50. For 43: ones digit 3 < 5, so 43 → 40.

Estimation in Practice

Rounding shines in estimation. Before computing 298 × 4 exactly, estimate: 300 × 4 = 1,200. Your exact answer should be close to 1,200 (it is 1,192). This technique catches errors and builds confidence. Practice by estimating answers before calculating exactly — compare the two and notice how close your estimates become with practice.

Practice Examples

Example 1: Round 47 to the nearest ten

1. Look at the ones digit: 7
2. 7 is 5 or greater, so round up
3. 47 → 50

Answer: 50

Example 2: Round 123 to the nearest ten

1. Ones digit is 3
2. 3 is less than 5, so round down
3. 123 → 120

Answer: 120

Example 3: Estimate: 38 + 52

1. Round 38 to 40
2. Round 52 to 50
3. 40 + 50 = 90 (exact answer is 90)

Answer: ≈ 90