How to estimate before you calculate - �鶹��ҳ�� Bitesize

Estimating is used to help predict the answer to a calculation.
We use estimation to make calculations more manageable and to give us an idea of the answer.
Estimation is used in the construction industry, for example, when buying materials and planning labour.

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Click to see a step-by-step slideshow.
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STEP 1 - The mobile phone is £18.95 per month. The contract is for 12 months. This means we need 12 lots of 18.95.
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STEP 2 - We can round 18.95 up to 20, as it is easier to multiply by 20 than 18.95. 20 is also closer to 18.95 than 15.
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STEP 3 - We then round 12 down to 10. Multiplying by 10 is easier than multiplying by 12.
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STEP 4 - Our estimation then becomes 10 x 20 = 200.
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STEP 5 - The total estimated cost of the phone contract is £200.

What is estimation?

Estimation is used to predict the answer to a calculation. Estimation uses round numbers in a calculation to make it quicker or easier to get an approximate answer.

For example, if we were to estimate the answer to 11.87 x 4.876. We could use the calculation 10 x 5 = 50. This gives us a sensible estimate that we can calculate in our head.

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What is estimation?

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