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NEXUS

- EDEXCEL GCSE
- AQA GCSE
- OCR GCSE
- EDUQAS GCSE

**Rounding** simplifies a number. Imagine walking into a shop an 5 items are 99p. Your brain will round each item to a pound and realise the total cost is about £5!

If we round 236 to the nearest hundred, we will either get 200 or 300. If the number is **250 or more**, it will round **up **to 300, if **less** then it will round **down** to 200. 236 is closer to 200, so will round to 200.

Decimals can be very long (or can go on forever!) To round a decimal we can use decimal places. We count the number of digits past the decimal place we want.

Rounding 0.1351 to 2 decimal places will either give us 0.13 or 0.14. We look at the 'next digit' to work out what will happen. If the 'next digit' is **5 or more**, it will round **up**, if **less** then it will round **down**. 5 is **5 or more**, so will round **up** to 0.14.

Some numbers, like distances in space, can get very big. Significant figures will work with any number, even if its not a decimal. The rules are the same for decimal places, but we do not start counting at the decimal point any more. Significant figures count the number of digits after the first non-zero digit.

Rounding 36781 to 2 significant figures will either give us 36000 or 37000. We look at the 'next digit' to work out what will happen. If the 'next digit' is **5 or more**, it will round **up**, if **less** then it will round **down**. 7 is **5 or more**, so will round **up** to 37000.

Ultimate members get access to four additional questions with full video explanations.