Lesson details

Key learning points

  1. In this lesson, we will learn how to estimate and solve problems using estimation.

Licence

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6 Questions

Q1.
A classroom is measured 5.4 x 3.4 metres, measured to 1 d.p. Calculate the lower bound of the area of the room.
17.889 π‘π‘š^2
Correct answer: 17.9225 π‘π‘š^2
18.36 π‘π‘š^2
18.8025 π‘π‘š^2
Q2.
James ran a distance of 400m in a time of 25.2 seconds. The distance of 400m was measured to the nearest 10 metres. The time of 25.2 was measured to the nearest tenth of a second. Work out the upper bound James' average speed.
15.7 m/s
16.04 m/s
16.07 m/s
Correct answer: 16.10 m/s
Q3.
James ran a distance of 400m in a time of 25.2 seconds. The distance of 400m was measured to the nearest 10 metres. The time of 25.2 was measured to the nearest tenth of a second. Work out the lower bound James' average speed.
Correct answer: 15.64 m/s
15.67 m/s
15.69 m/s
15.71 m/s
Q4.
Carl measured the length and width of a rectangle. He measured the length to be 19cm correct to the nearest centimetre. He measured the width to be 20cm correct to the nearest 10cm. Calculate the lower bound for the area of this rectangle.
Correct answer: 277.5 cm^2
292.5 cm^2
370 cm^2
380 cm^2
Q5.
6 heights are listed, given to one decimal place: 4.6cm, 6.3cm, 9.8cm, 3.2cm, 5.7cm, 3.6cm. Work out the greatest possible mean.
5.48cm
5.53cm
Correct answer: 5.58cm
5.98cm
Q6.
A circle has an area of 130cm^2 to the nearest 10cm^2. Work out the upper bound of the radius. Give your answer to 3 d.p.
39.789
6.308
6.433
Correct answer: 6.555

6 Questions

Q1.
Estimate the total cost of 32 books at Β£178 each and 57 markers at Β£22.30 each.
Β£6700
Β£6715
Β£6967
Correct answer: Β£7200
Q2.
Student A estimated that 23.5 x 91 = 1800. Student B estimated that 23.5 x 91.4= 2160. What did student B do?
Nothing, they just multiplied the original values
Rounded both values down and then multiplied.
Correct answer: Rounded both values to the nearest integer and then multiplied
Rounded both values to to 1 s.f. and then multiplied
Q3.
Work out an estimate for 9.97% of 3967
300
392.7
396.7
Correct answer: 400
Q4.
Estimate the value of: 6.2 + 7.9 x 3.2 - 9.8
18
Correct answer: 20
21.68
32
Q5.
I estimated that 7.85 x 29 = 240. Why is my estimated answer more than my exact answer?
Correct answer: Because both values were rounded up meaning answer will be greater
It shouldn't be. Estimation is incorrect
Only one value was rounded up and so answer is only a little greater than the exact value
Q6.
Find an estimate for √78
8
8.5
Correct answer: 8.9
9

Lesson appears in

UnitMaths / Accuracy and estimation