Practice Approximation in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

A value intentionally chosen to be close to but not exactly equal to the true value, with a known or estimated error.

We use 3.14 for π, knowing it's not exactly right but close enough.

Showing a random 20 of 50 problems.

Example 1

medium
Compute the percent error when π is approximated as 3.14 (use the true value 3.14159).

Example 2

medium
Use the first-order linear approximation a+ϵ≈a+ϵ2a to estimate 101.

Example 3

easy
Round 0.0467 to two decimal places.

Example 4

hard
A circular table has measured diameter 1.20 m (with ±0.005 m uncertainty). Approximate its area and its uncertainty.

Example 5

easy
Estimate 198×52 using rounding, then compute the exact answer and find the percent error.

Example 6

easy
Estimate 50 to one decimal place without a calculator.

Example 7

challenge
Estimate 2≈1.4 and use one Newton step x1=12(x0+2x0) to improve it.

Example 8

medium
Use the approximation π≈227 to estimate the circumference and area of a circle with radius 14 cm. Compare with the decimal approximation π≈3.14159.

Example 9

medium
To estimate 20 between consecutive tenths, which two values bracket it?

Example 10

easy
True or false: every approximation has some error.

Example 11

easy
Round π to two decimal places.

Example 12

medium
A budget of $2980 is rounded to $3000 for a report. What is the rounding error, and is it an over- or under-estimate?

Example 13

challenge
A surveyor estimates a hill's height using the angle of elevation. If the measured angle is 30.0∘±0.5∘ and the horizontal distance is 200 m (exact), give the approximate height and its uncertainty.

Example 14

easy
Estimate π to 1 decimal place.

Example 15

medium
Approximate 1,492÷7 to the nearest hundred.

Example 16

hard
Use the linear approximation (1+x)n≈1+nx for small x to estimate 1.0210.

Example 17

easy
Approximate 17 to the nearest whole number.

Example 18

easy
Approximate 227 as a decimal to two places.

Example 19

hard
What is the relative error if a measurement of 50.0 kg is off by 0.4 kg?

Example 20

easy
Round 6849 to the nearest hundred.