Estimating numerical calculations

12 questions

1. ___________ figures are the digits in a number that contribute to the accuracy of the number. The first __________ figure is the first non-zero digit.
2. 5689 rounded to 1 s.f. is ___.
3. 428.62 rounded to 1 s.f. is ___.
4. 428.62 rounded to 2 s.f. is ___.
5. Sam correctly rounds an integer to the nearest 10. Sam's answer is 80. What could Sam's unrounded integer be?
6. Laura correctly rounds a number to 1 significant figure. Her answer is 8. What could Laura's unrounded number be?
7. A quick ___ for a calculation is obtained from using approximate values, often rounded to 1 significant figure.
8. Which of the following is the most accurate estimate calculation for 856 × 465?
9. Which of the following are good, quick estimate calculations for 578 ÷ 1.785?
10. Which of the following are good, quick estimate calculations for {4.56\times8.95} \over {7.65}?
11. Which of the following are correct estimates for {18.96\times2.15} \over {0.546}?
12. Given Alex is of average secondary school pupil height. An estimate of the height of the elephant is ___ m. Give your answer to 1 decimal place.

License: OGL