Decimal Places & Significant Figures Round Off Practice 1
This section contains 6 focused practice questions designed to reinforce the rules and techniques for rounding off to decimal places and significant figures.
Students can use these questions for quick practice, revision, or to check their understanding and accuracy when rounding numbers.
Related Lessons:
Practice 1 - Question 1
Express \(\frac{3}{158}\) as a decimal, giving your answer correct to 3 significant figures.
Solution:
Pressing our calculator, we get:
\(\frac{3}{158}=0.0189873 = 0.0190 (3s.f.)\)
Practice 1 - Question 2
Round of 3.046723 to 3 decimal places.
Solution:
3.046723=3.047 (3d.p.)
Practice 1 - Question 3
Express \(\frac{136}{333}\) as a
- recurring decimal
- decimal correct to 5 decimal places
- decimal correct to 3 significant figures
Solution:
a) To round to recurring decimals, since the value “408” is repeated, we will put a dot on top of the value “4” and “8”:
\(\frac{136}{333}=0.408408408 = 0.\dot{4}0\dot{8}\)
b) \(\frac{136}{333}=0.408408408 = 0.40841 (5d.p.)\)
c) \(\frac{136}{333}=0.408408408 = 0.408 (3s.f.)\)
Practice 1 - Question 4
Evaluate \(\frac{\sqrt{100.35}-3.86}{4.65-\left(1.37\right)^3}\)
- show all the digits on your calculator
- correct to 2 significant figures
Solution:
a) \(\frac{\sqrt{100.35}-3.86}{4.65-\left(1.37\right)^3}=2.96225608\)
b) To round off to 2s.f, the answer is 3.0, and note that in this case, the trailing “0” is significant.
\(\frac{\sqrt{100.35}-3.86}{4.65-\left(1.37\right)^3}=3.0\)
Practice 1 - Question 5
Evaluate, taking the positive square root, correct to 2 decimal places the expression \(\frac{99\times\sqrt{266}-76^3}{\sqrt[3]{56}+8}.\)
Solution:
\(\frac{99\times\sqrt{266}-76^3}{\sqrt[3]{56}+8}\)
\(=-36983.46432\)
\(=-36983.46 (2d.p.)\)
Practice 1 - Question 6
Evaluate \(\frac{\sqrt[3]{54.872}}{\left(1-0.921\right)^2}\), giving your answer correct to
- 2 decimal places
- 2 significant figures
Solution:
Pressing our calculator, we will get the value 608.8767826. So the round off answers are:
a) 608.88 (2.d.p.)
b) 610 (2s.f.)
Watch Full Solution Step By Step
Below is the complete step-by-step solution to the six questions above on decimals and significant figures. The video explanation provides a clearer presentation of the concepts, and students are encouraged to watch it to strengthen their understanding.