Mastering Accuracy: Practice Questions & Solutions

Welcome to your practice zone! Here, you’ll find questions designed to test your understanding of Decimal Places, Significant Figures, and Rounding. These are crucial skills for your IB Math exams and Internal Assessments! Take your time to work through each question. Remember, the best way to learn is by doing! Once you’re done, you can check your answers with my detailed video solutions below.

Watch Solutions Video

Practice Questions

Set A

1) For each of the following scenarios, determine the appropriate rounded value based on the given precision requirements:

a. A company’s annual profit was $5555. State this profit to 3 significant figures.

b. During an experiment, the measured length of an object was 8.295 cm. Round this measurement to 2 significant figures.

c. The population of a small town was reported as 41672 people. Express this population to 1 significant figure.

d. A very small particle had a mass of 0.000781 grams. Give this mass to 2 significant figures. 

e. Calculate $\sqrt{37}$, and then round your answer to 1 decimal place. (Hint: You’ll need a calculator)

  • $5560
  • 8.3
  • 40000
  • 0.00078
  • $\sqrt{37}$ = 6.0827625… $\approx$ 6.1

Set B

2) Perform the following calculations and round your final answers as stated:

a. A tourist from the USA spent $7243 on a trip to Europe. How much is this in Euros (EUR), rounded to 3 significant figures? (Use: 1 USD=0.93 EUR)

b. An item is priced at 12.678 EUR in a duty-free shop. Convert this price to US Dollars (USD), rounded to 2 significant figures. (Use: 1 EUR=1.07 USD)

c. A Japanese company made a purchase worth 87355 JPY. How much is this in British Pounds (GBP), rounded to 1 significant figure? (Use: 1 GBP=195 JPY)

  • 6735.99 $\approx$ 6740 EUR
  • 13.56546 $\approx$ 14 USD
  • 447.9743… $\approx$ 400 GBP

External Exam Question

3) [Maximum 4]

The volume of a sphere is 150 $cm^2$ correct to 2 significant figures. Calculate the radius of the sphere correct to 2 significant figures. 

$ V = \frac{4}{3}\pi r^{3}$

$150 = \frac{4}{3}\pi r^{3}$ (M1)

$r^{3} = 150 (\frac{3}{4\pi})$

$r = \sqrt[3]{150 (\frac{3}{4\pi})}$ (M1)

$r = 11.9366207…$ (A1)

$r \approx 12 cm^3$ (A1)

Note: The distribution of the marks depends on the actual markscheme.

Keep Practicing!

Well done for attempting these questions! It’s perfectly fine if you got some wrong – that’s how we learn. Now, watch my video below where I walk you through each problem step-by-step, explaining the correct answers and common mistakes.

The more you practice, the more confident you’ll become! If you found any of these topics tricky, don’t hesitate to revisit Accuracy and Measurement for a quick refresh. Got questions about these solutions or anything else? Drop a comment below! Your feedback helps us create better lessons. And for more detailed IB Math help and IA support, check out our services. Don’t forget to subscribe to our channel Learn math by example for all our latest math lessons and tips!

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