6 — Rounding and Estimation

Rounding and Estimation

Solution & Explanation · ID: BB108ECE

Question

Use front-end estimation for 456 + 213 + 789.

Hint

Use only the hundreds digits and ignore the rest.

Concept

Front-end estimation uses only the leading digits (front digits) of each number to make a quick estimate.

Show Answer

1,400

Show Solution
1

Identify the front digits: 456 → 400, 213 → 200, 789 → 700

2

Add the front-end estimates: 400 + 200 + 700 = 1,300

3

Look at remaining digits: 56 + 13 + 89 ≈ 150

4

Adjust the estimate: 1,300 + 100 = 1,400

Three numbers shown vertically: 456, 213, 789. Front digits 4, 2, 7 are highlighted in blue, showing 400 + 200 + 700 = 1,300. Remaining digits 56, 13, 89 are shown separately with ≈150. Final calculation shows 1,300 + 100 = 1,400.