Lesson details

Key learning points

  1. In this lesson, we will learn how to estimate the answer to a calculation by rounding all the values to one significant figure before calculating.

Licence

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5 Questions

Q1.
What is the upper bound of 21 cm rounded to the nearest centimetre?
20.5 cm
21.4 cm
21.49 cm
Correct answer: 21.5 cm
Q2.
The population of Yorkshire is 5 400 000 to two significant figures, what is the greatest possible number of people who live in Yorkshire?
5 400 500
Correct answer: 5 449 999
5 450 000
5 500 000
Q3.
What is the lower bound for 120, rounded to the nearest 5?
115
115.5
Correct answer: 117.5
119.5
Q4.
A rectangle has sides of 5.6 cm and 8.4 cm rounded to the nearest millimetre. What is the lower bound for the perimeter?
13.9 cm
14.1 cm
Correct answer: 27.8 cm
28.2 cm
Q5.
The side length of a square is rounded to the nearest tenth of a centimetre and used to calculate its area of 38.44 cm². What is the lower bound for the perimeter of the square?
Correct answer: 24.6 cm
6.15 cm
6.2 cm
9.61 cm

5 Questions

Q1.
Which calculation would we do to estimate the answer to 467 ÷ 0.48?
400 ÷ 0.4
460 ÷ 0.5
470 ÷ 0.5
Correct answer: 500 ÷ 0.5
Q2.
2. Estimate the answer to 34 x 890
24 000
Correct answer: 27 000
30 260
32 000
Q3.
3. Estimate the answer to 273 ÷ (0.64 + 0.853)
180
20
Correct answer: 200
45
Q4.
Which of the following calculations would have as estimated answer of 1000?
112 x 8.95
1587 ÷ 0.487
251 x 3.704
Correct answer: 9604 x 0.1489
Q5.
5. Would the estimate for 743 x 3299 be an overestimate or an underestimate?
Not enough information to say
Overestimate
Correct answer: Underestimate

Lesson appears in

UnitMaths / Rounding and Estimating