Rounding Numbers
Year 3 students learn to round whole numbers to the nearest 10 and 100, developing number sense and the ability to estimate quickly.
What You Need to Know
Key Concept Diagram
Rounding to the nearest 10 looks at the ones digit: 5 or more rounds up, less than 5 rounds down
Rounding to the nearest 100 looks at the tens digit to decide which hundred to use
A number line helps visualise which ten or hundred a number is closest to
Rounding makes mental calculations and estimates faster and easier
Key Vocabulary
Round
Replace a number with a simpler approximate value
Nearest 10
The multiple of 10 that a number is closest to
Nearest 100
The multiple of 100 that a number is closest to
Estimate
A quick approximate answer found using rounding
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
Round 47 to the nearest 10.
Question 2
Round 342 to the nearest 100.
Question 3
Which number rounds to 80 when rounded to the nearest 10?
Key Concepts Summary
- ●Rounding to the nearest 10 looks at the ones digit: 5 or more rounds up, less than 5 rounds down
- ●Rounding to the nearest 100 looks at the tens digit to decide which hundred to use
- ●A number line helps visualise which ten or hundred a number is closest to
- ●Rounding makes mental calculations and estimates faster and easier