Estimation

The Maths Habit

  1. Round 38 260 to 2 significant figures.

    38 000

  2. Round 0.0749 to 1 significant figure.

    0.07

  3. Round 6.95 to 2 significant figures.

    7.0

How many times does your
heart beat in a day?

About 100 000

Estimate
A sensible answer that is close to the exact one.

4.8 × 21.35 × 20

Is it closest to 18, 180 or 1800?

0.31 × 587 0.3 × 600 = 180

Estimate the value. Round each number to 1 significant figure first.

3.87↓4×61.4↓60
= 240
Answer240

Estimate the value. Round each number to 1 significant figure first.

7.3↓7×48.6↓50
= 350
Answer350

Estimate the value. Round each number to 1 significant figure first.

3.87↓4×61.4↓60
= 240
Answer240

Estimate the value. Round each number to 1 significant figure first.

5.8↓6×71.5↓70
= 420
Answer420

Estimate the value. Round each number to 1 significant figure first.

3.87↓4×61.4↓60
= 240
Answer240

Estimate the value. Round each number to 1 significant figure first.

0.38↓0.4×527↓500
= 200
Answer200

Estimate the value. Round each number to 1 significant figure first.

3.87↓4×61.4↓60
= 240
Answer240

Estimate the value. Round each number to 1 significant figure first.

28.7↓30×6.3↓6
= 180
Answer180

Estimate the value. Round each number to 1 significant figure first.

3.87↓4×61.4↓60
= 240
Answer240

Estimate the value. Round each number to 1 significant figure first.

812↓800×4.6↓5
= 4000
Answer4000

Estimate

613 ÷ 28.7

Estimate

(18.9 + 41.2) ÷ 5.8

Estimation worksheet, page 1

Estimation worksheet, page 2

Answer sheet

  1. Sam says 19.8 × 5.1 = 1009.8. Use an estimate to show that he must be wrong.

    20 × 5 = 100

  2. A ticket costs £18.75. Estimate the cost of 32 tickets.

    £600

A heart beats 72 times a minute.
Estimate the beats in 24 hours.

70 × 60 × 20 = 84 000

  1. Estimate 4.2 × 78.9 by rounding each number to 1 significant figure.

    320

  2. Estimate (58.6 − 19.2) ÷ 4.1 by rounding each number to 1 significant figure.

    10

  3. Is 0.48 × 612 closest to 30, 300 or 3000? Show how you know.

    300: 0.5 × 600
Exit tickets to print