IGCSEMaths: ExtendedCIETopic Questions1. Number1.13 Rounding, Estimation and Bounds

Syllabus Edition

First teaching 2021

Last exams 2024

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Rounding, Estimation and Bounds (CIE IGCSE Maths: Extended)

Topic Questions

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1
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A rectangle measures 8.5 cm by 10.7 cm, both correct to 1 decimal place.

Calculate the upper bound of the perimeter of the rectangle.


 ............................................ cm

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2
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The space allowed for each tent is a rectangle measuring 8 m by 6 m, each correct to the nearest metre.
 
Calculate the upper bound for the area of the space allowed for each tent.
 

 ............................................ m2

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3
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The formula  s equals 1 half a t squared  is used to calculate the distance, s, travelled by a bicycle.

When a equals 3 and t equals 10, each correct to the nearest integer, calculate the lower bound of the distance, s.

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4
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Every page of the newspaper is a rectangle measuring 43 space text cm end text by 28 space text cm end text, both correct to the nearest centimetre.

Calculate the upper bound of the area of a page. 
 

........................................ cm2

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5
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On one day, the number of members using the exercise machines was 40, correct to the nearest 10.
Each member used a machine for 30 minutes, correct to the nearest 5 minutes.

Calculate the lower bound for the number of minutes the exercise machines were used on this day.

......................................... min

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6
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The dressmaker measures a length of fabric as 600 m, correct to the nearest 5 metres.
He cuts this into dress lengths of 9 m, correct to the nearest metre.
 
Calculate the largest number of complete dress lengths he could cut.

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1
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Priya has 50 identical parcels.
Each parcel has a mass of 17 kg, correct to the nearest kilogram.
 
Find the upper bound for the total mass of the 50 parcels.
 

.............................................. kg

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2
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i)
29 parcels each have a value of $68.
 
By writing each of these numbers correct to 1 significant figure, find an estimate for the total value of these 29 parcels.
 
$ .................................................. [1]
ii)
Without doing any calculation, complete this statement.
 
The actual total value of these 29 parcels is less than the answer to part (i) because ...................... [1]

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3
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Each side of a regular octagon has a length of 18 mm, correct to the nearest 0.5 mm

q4-4ma1-2h-qp-jan22-paper2-igcse-maths

i)
Write down the lower bound of the length of each side of the octagon.
[1]

ii)
Write down the upper bound of the length of each side of the octagon.
[1]

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4
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The mass of a cat is 4.3 kg correct to 2 significant figures.

i)

Write down the upper bound of the weight of the cat.
 

........................... kg [1]

ii)

Write down the lower bound of the weight of the cat.
 

........................... kg [1]

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5
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The length of a book is 33.8 cm, correct to one decimal place.

i)
Write down the lower bound of the length of the book.

.............................................. cm [1]

ii)
Write down the upper bound of the length of the book.

.............................................. cm [1]

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6
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To the nearest 1000, there are 18 000 people at a festival.

i)

Write down the minimum possible number of people at the festival.

[1]

ii)

Write down the maximum possible number of people at the festival.

[1]

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7
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The length of a table is 110 cm to the nearest cm

Complete the error interval.

.................cm ⩽ length < .................cm

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8a
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The length of each side of a regular pentagon is 8.4 cm to 1 decimal place.

Complete the error interval for the length of one side.

....................cm ⩽ length < ....................cm

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8b
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Complete the error interval for the perimeter.

....................cm ⩽ perimeter < ....................cm

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1
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A road is 4530 m long, correct to the nearest 10 metres.
Kirsty drove along the road in 205 seconds, correct to the nearest 5 seconds.

The average speed limit for the road is 80 km/h.

Could Kirsty's average speed have been greater than 80 km/h?
You must show your working.

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2
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The dimensions of a rectangular floor are to the nearest 0.1 metres.

q25-paper2h-nov2017-aqa-gcse-maths

A force of 345 Newtons is applied to the floor.
The force is to the nearest 5 Newtons.

pressure space equals space force over area

Work out the upper bound of the pressure.
Give your answer to 4 significant figures.
You must show your working.

........................N/m2

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3
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A £1 coin weighs 8.75 g, correct to the nearest 0.01 g.
Mitul weighs the contents of a large bag of £1 coins.
The coins weigh 2.63 kg, correct to the nearest 10 g.

Mitul says

   I am sure that the bag contains exactly £300 because, using bounds,
   2625 ÷ 8.755 = 299.8 to 1 decimal place.

Show that Mitul may not be correct.

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4
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Edith’s van can safely carry a maximum load of 920 kilograms.

She wants to use her van to carry

30 sacks of potatoes, each of mass 25 kilograms to the nearest kilogram

and

20 sacks of carrots, each of mass 7.5 kilograms to 1 decimal place.

Can she definitely use her van safely in one journey?

You must show your working.

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5
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The length of a roll of ribbon is 30 metres, correct to the nearest half-metre.

A piece of length 5.8 metres, correct to the nearest 10 centimetres, is cut from the roll.

Work out the maximum possible length of ribbon left on the roll.

...................metres

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6
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Claudine cycled a distance of 53 km in 2.7 hours.
The distance is measured correct to the nearest km.
The time is given correct to 1 decimal place.

Calculate the lower and upper bounds of her average speed.

Give your answers correct to 2 decimal places.

Lower bound = ................................ km/h
Upper bound = ................................ km/h

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7
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Sunil makes 7.5 litres of soup, correct to the nearest 0.5 litre.
He serves the soup in 300 ml portions, correct to the nearest 10 ml.
24 people order this soup.

Does Sunil definitely have enough soup to serve the 24 people?
Show how you decide.

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