Skip to content
Auralith
Log inGet started

Year 7 · Maths · Place value and ordering · Lesson 2

Rounding and significant figures

Round numbers to the nearest 10, 100 and 1000, to decimal places and to significant figures, and use rounding to estimate.

Whiteboard video lesson: Rounding and significant figures

25-minute video lesson

Teaching, worked examples and 20 practice questions solved step by step.

Watch free for a month

What your child will learn

  • Round to the nearest 10, 100 or 1000
  • Round to decimal places
  • Round to significant figures
  • Find bounds for a rounded number
  • Estimate calculations

The method

  1. Find the digit you are rounding to.
  2. Look at the next digit: 5 or more round up, 4 or less round down.
  3. Significant figures start at the first non-zero digit.
  4. Keep place value with zeros.

Key words: round, decimal place, significant figure, estimate, nearest.

Worked examples

The first three practice questions from the lesson, with every step.

Question 1

Round 83 to the nearest 10.

  1. Step 1: Between 80 and 90
  2. Step 2: Halfway: 85
  3. Step 3: 83 is below halfway: round down

Answer: 80

Question 2

Round 275 to the nearest 10.

  1. Step 1: Between 270 and 280
  2. Step 2: Halfway: 275
  3. Step 3: 275 is at or above halfway: round up

Answer: 280

Question 3

Round 1449 to the nearest 100.

  1. Step 1: Between 1400 and 1500
  2. Step 2: Halfway: 1450
  3. Step 3: 1449 is below halfway: round down

Answer: 1400