Mini Minds Hub · Free printable
Significant Figures: Free Printable Worksheet for Year 8
- ForYear 8
- StageKey Stage 3
- CostFree
- FormatPrintable PDF
Significant Figures is a free printable maths worksheet for Year 8 (ages 12 to 13), in Key Stage 3. Children round whole numbers and decimals to a given number of significant figures. Page 2 gives the grown-up notes on how to use the sheet, help for children who find it hard, a stretch idea and the answers.
It comes from the Mini Minds Hub, the free library of printables from Jaques of London, the British games and toy company that has been making games for families since 1795. Print both pages, give page 1 to your child and keep page 2 for yourself. Black and white printing works well.
What is on the sheet
Children round eight numbers to 1, 2 or 3 significant figures. Some are whole numbers and some are decimals. Some decimals begin with zeros, so children must count with care. One number appears more than once, rounded to different degrees of accuracy, which shows how the answer changes. There is space to answer each question on the page.
- 4567 to 1 s.f.
- 4567 to 2 s.f.
- 3.1416 to 3 s.f.
- 0.0523 to 1 s.f.
- 0.05234 to 3 s.f.
- 7849 to 2 s.f.
- 98765 to 3 s.f.
- 0.00678 to 2 s.f.
A worked example
Round 0.003962 to 2 s.f.
This example uses a different number from every question on the sheet. It shows two ways to think about the same job.
Method 1: underline and count- Find the first digit that is not zero. It is the 3. Underline it. The zeros before it are only place holders.
- Count 2 significant figures: the 3 and the 9. The next digit is 6, so that is the deciding digit.
- 6 is 5 or more, so round up. The 9 becomes 10, so write 0 and carry 1 to the 3, which becomes 4.
- Write 0.0040. The final zero stays, because it shows the number is given to 2 s.f.
- The two numbers with 2 s.f. that sit either side are 0.0039 and 0.0040.
- The halfway point between them is 0.00395.
- 0.003962 is a little above 0.00395, so it is closer to 0.0040.
Build the skill in four steps
Find the first significant figure
Move from the left and find the first digit that is not zero. That is where counting starts. Underline it before doing anything else.
Count the digits you need
Count along from the underlined digit. If the question says 2 s.f., keep two digits in total. Draw a small line after the last digit you keep.
Look at the next digit
The digit just after your line decides the rounding. If it is 5 or more, round the last kept digit up. If it is 4 or less, leave it.
Keep the size of the number
Digits that are dropped from a whole number must be replaced with zeros, so the number stays about the same size. Then check that your answer is close to the original.
Why do we round to significant figures?
Some numbers have more digits than we need. A calculator may show a long string of digits, but a measurement is rarely exact. Rounding to significant figures keeps the digits that matter most and drops the rest. It works the same way for large numbers and very small ones, which is why it is useful in maths and science.
Rounding to decimal places counts from the decimal point. Rounding to significant figures counts from the first digit that is not zero. That small difference trips up many learners, especially with decimals that start with zeros. Practising with a mix of whole numbers and decimals helps children see what stays the same and what changes.
Skills and curriculum link
- Rounding to significant figures
- Place value
- Working with decimals
- Careful counting
- Estimating and checking
Facts that help
- Counting starts at the first non zero digitZeros at the very start of a decimal are not significant figures. They show where the other digits sit.
- The next digit decidesLook only at the digit straight after the last one you keep. If it is 5 or more, round up. Otherwise leave the last digit as it is.
- Zeros can be place holdersWhen you round a whole number, replace the dropped digits with zeros. This stops the number from shrinking to a much smaller size.
- Check the sizeA rounded number should be close to the original. If your answer looks much bigger or smaller, check the place value again.
Key words
- Significant figureA digit that carries meaning in a number. Counting starts at the first digit that is not zero.
- RoundChange a number to a simpler one that is close to it.
- Place valueThe value a digit has because of where it sits in the number.
- Place holderA zero that keeps other digits in the right place without adding to the count.
- DecimalA number with a decimal point, used to show parts of a whole.
- Deciding digitThe digit straight after the last one you keep. It tells you whether to round up or leave as it is.
How to use it
- Print both pages. Page 1 is for your child. Keep page 2, which has the notes and answers.
- Ask your child to underline the first significant figure in each number before they round it.
- For the first question or two, work together and talk through each choice. Ask which digit decides the rounding.
- Let your child try the rest alone. Then check against the answers on page 2 and ask how they worked each one out.
- Come back to the sheet another day. Repeating a familiar activity builds confidence.
Help, stretch and game ideas
If it feels too hard
Rewrite each number in a place value table first, one digit in each column. Cross out any zeros at the start of a decimal. Then count the columns you need, and circle the deciding digit before rounding. Try the whole number questions before the decimals.
To stretch confident children
Write a number that rounds to 5000 to 1 s.f. and a different number that rounds to 5100 to 2 s.f. Then try to find the smallest and largest numbers that fit each rule. Explain how you know.
Make it a game
Collect numbers from a newspaper, a food label or a shop receipt and round each one to 2 s.f. A partner checks the answer. Score a point for each correct one, and a bonus point for explaining the deciding digit.
Mistakes to watch for
Watch forA child counts the zeros at the start of a decimal as significant figures, so the answer has the wrong size.
Try thisCross out the leading zeros first, then underline the first digit left. Start counting from that digit.
Watch forWith a whole number such as 6283 to 2 s.f., a child writes 63 and forgets the zeros.
Try thisCompare the size of the answer with the original. Replace the dropped digits with zeros so it stays close to 6283.
Watch forA child looks at the wrong digit and rounds using the last digit of the number.
Try thisDraw a line after the last digit you keep. Circle only the digit straight after the line. That is the one that decides.
Talk about it
- How do you know where to start counting significant figures?
- Why are zeros at the start of a decimal different from other zeros?
- What does the deciding digit tell you?
- How can you check that your rounded answer is sensible?
- When might it be useful to round a number like this in real life?
- How is rounding to significant figures different from rounding to decimal places?
Take it off the page
Number hunt
Find numbers around the house, such as on packets, bills or books. Write them down and round each to 1 s.f. and 2 s.f. Compare the two answers.
Place value cards
Write digits on small pieces of paper and lay out a number. Cover the digits you drop and replace them with zero cards where needed.
Closest number challenge
One person writes a long number. Everyone else writes the rounded version to a chosen number of significant figures. The closest correct rounding wins the round.
Who it is for
Parents
Sit with your child for the first question, then let them lead. Ask them to say which digit decides each rounding. Praise careful thinking, not just correct answers. Use page 2 to check together and talk about any slips.
Teachers
Use it as a starter, a plenary, an early finisher task, homework or a table activity. It needs no preparation beyond printing. Page 2 gives support and stretch ideas for mixed ability groups, and the answers make marking quick.
Home educators
Print it as part of a wider maths plan. It fits well after work on place value and rounding. You can print it again for brothers and sisters or for revision a few weeks later, using the help and stretch ideas to adjust the challenge.
Where this fits in maths
Before this, children learn place value, rounding to the nearest 10, 100 and 1000, and rounding decimals to a number of decimal places. Those skills help children see which digits matter in a number.
After this, children use significant figures in work on estimating, standard form and accuracy in science and maths. Being confident with leading zeros and place holders makes that later work easier.
Questions parents and teachers ask
- What age is Significant Figures for?
It is written for Year 8 (ages 12 to 13), in Key Stage 3. It also works as revision for older children, or as a stretch task for confident learners in Year 7.
- What will children practise?
They practise rounding whole numbers and decimals to a given number of significant figures. That includes place value, working with decimals, and careful counting from the first digit that is not zero.
- Do the answers come with the sheet?
Yes. Page 2 is for the grown-up and includes the answers, along with notes on how to use the sheet, help for children who find it hard, and a stretch idea.
- What if my child finds it too hard?
Start with a place value table. Write each digit in its own column, cross out zeros at the start of a decimal, then count the digits you need. Try the whole number questions first and come back to the decimals later.
- Is it free?
Yes. It is free to print for home and classroom use. You can print it again for brothers and sisters or for revision.
- Can teachers use it in class?
Yes. Teachers can use it as a starter, plenary, early finisher task, homework or table activity. It needs no preparation beyond printing, and page 2 helps with support and stretch.
- Is this a screen free activity?
Yes. It needs only paper and a pencil, so it suits quiet time, rainy days and school holidays. Printing in black and white on plain A4 paper works well.
Preview the full PDF
Made by Jaques of London, making games for families since 1795. A printable supports classroom learning and does not replace a teacher.