Starter quiz
- Rounding means to change a number into another number that is approximately the same value, but is ______ to work with.
- 'easier' ✓
- 27 345 rounded to the nearest thousand is ______.
- '27 000' ✓
- Lucas buys a t-shirt costing £22.25. What is the cost of the t-shirt to the nearest pound?
- '£22.00' ✓
- Round 305.7298 to 1 decimal place.
- '305.7' ✓
- Round 0.06921 to 2 decimal places.
- '0.07' ✓
- Round 12.89528 to 2 decimal places.
- '12.90' ✓
Exit quiz
- Degree of accuracy shows how ______ a rounded number or measurement is.
- 'precise' ✓
- Select the numbers that do not round to 14 000 when rounded to the nearest thousand.
- 13 450 ✓
- 13 550
- 13 650
- 14 450
- 14 550 ✓
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- 54 528 is 54 500 to the nearest ...
- ten
- hundred ✓
- thousand
- ten thousand
- hundred thousand
-
- Jacob estimates how many pieces of pasta are in a bowl of pasta. Which of the following is the most appropriate degree of accuracy in this situation?
- Nearest integer
- Nearest ten ✓
- Nearest hundred
- Nearest thousand
-
- A charity is sending thank you cards to 160 people who have made donations. Stamps come in books of 12. How many books of stamps do they need to buy?
- '14' ✓
- Izzy buys a large bag of 75 chocolate bars. She puts them into boxes of 4 to sell for charity. How many boxes will Izzy have to sell?
- '18' ✓
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- When a number has been rounded you can make conjectures about what the unrounded number could have been.
- Rounding can be very useful in real life contexts particularly measure.
- When working in some real life contexts you are often working to a certain degree of accuracy.
- Numbers in different contexts will be rounded to a different degree of accuracy (e.g. distance when walking or flying).
Common misconception
The assumption that if a number ends in 2 zeros it must have been rounded to the nearest hundred.
Choose examples that round to the same value when rounded to the nearest ten and hundred in this case. E.g. 398, rounds to 400 to the nearest ten and 400 to the nearest hundred.
Keywords
Conjecture - A (mathematical) statement that is thought to be true but has not been proved yet.
Degree of accuracy - A degree of accuracy shows how precise a number or measurement is. E.g. to the nearest cm, nearest 10, 1 d.p., etc.
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