Estimation means finding an approximate answer to a calculation. Estimating involves rounding numbers to 1 or 2 significant figures before performing a calculation. The estimated answer would be close to the actual answer.
Estimation in calculations
Round the numbers in the calculation to 1 or 2 significant figures before performing the calculation to find an approximate answer.
Example 1
Estimate the value of14.467.9+2.16.
First, round all 3 numbers to an appropriate number of significant figures:
67.9↦68
2.16↦2
14.4↦14
Carry out the calculation with the rounded numbers:
14.467.9+2.16≈1468+2=1470=5
14.467.9+2.16≈5
Estimation with square roots
Square roots can be estimated by identifying square numbers near a number.
Example 2
Estimate the value of 74 to 1d.p.
74 is inbetween the square numbers 64 and 81.
64=881=9
74 is closer to 81 than 64.
Therefore, 74≈8.7
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Length:
Unit 1
Using estimation to check answers
Unit 2
Rounding errors and estimating
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Unit 3
Estimation
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FAQs - Frequently Asked Questions
What is estimation?
Estimation means finding an approximate answer to a calculation.
How do you find the estimate for square roots?
Estimates for square roots can be found by identifying the position of numbers between consecutive square numbers.
How do you estimate calculations?
Round the numbers to an appropriate number of significant figures, then calculate with these numbers.