Give feedback
Chapter Overview
Learning Goals
Learning Goals
Maths
Summary
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.
Round the numbers in the calculation to $1$ or $2$ significant figures before performing the calculation to find an approximate answer.
Estimate the value of $\dfrac{67.9+2.16}{14.4}$.
First, round all $3$ numbers to an appropriate number of significant figures:
$67.9 \mapsto 68$
$2.16 \mapsto 2$
$14.4 \mapsto 14$
Carry out the calculation with the rounded numbers:
$\dfrac{67.9+2.16}{14.4}\approx \dfrac{68+2}{14} = \dfrac{70}{14} = 5$
$\underline{\dfrac{67.9+2.16}{14.4} \approx 5}$
Square roots can be estimated by identifying square numbers near a number.
Estimate the value of $\sqrt{74}$ to $1\space d.p.$
$74$ is inbetween the square numbers $64$ and $81$.
$\sqrt {64} = 8 \\\sqrt {81}= 9$
$74$ is closer to $81$ than $64$.
Therefore, $\underline{\sqrt{74} \approx 8.7}$
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.
Round the numbers in the calculation to $1$ or $2$ significant figures before performing the calculation to find an approximate answer.
Estimate the value of $\dfrac{67.9+2.16}{14.4}$.
First, round all $3$ numbers to an appropriate number of significant figures:
$67.9 \mapsto 68$
$2.16 \mapsto 2$
$14.4 \mapsto 14$
Carry out the calculation with the rounded numbers:
$\dfrac{67.9+2.16}{14.4}\approx \dfrac{68+2}{14} = \dfrac{70}{14} = 5$
$\underline{\dfrac{67.9+2.16}{14.4} \approx 5}$
Square roots can be estimated by identifying square numbers near a number.
Estimate the value of $\sqrt{74}$ to $1\space d.p.$
$74$ is inbetween the square numbers $64$ and $81$.
$\sqrt {64} = 8 \\\sqrt {81}= 9$
$74$ is closer to $81$ than $64$.
Therefore, $\underline{\sqrt{74} \approx 8.7}$
Rounding errors and estimating
FAQs
Question: What is estimation?
Answer: Estimation means finding an approximate answer to a calculation.
Question: How do you find the estimate for square roots?
Answer: Estimates for square roots can be found by identifying the position of numbers between consecutive square numbers.
Question: How do you estimate calculations?
Answer: Round the numbers to an appropriate number of significant figures, then calculate with these numbers.
Theory
Exercises
© 2020 – 2023 evulpo AG
Your data protection
We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners who may combine it with other information that you’ve provided them or that they’ve collected from your use of their services. By clicking on either "Accept cookies" or "Necessary cookies only", you agree to this (read more in our Privacy Policy). Privacy Policy