Rounding, Estimation & Bounds (Cambridge (CIE) IGCSE Maths: Extended): Exam Questions

Write 57.3997 correct to 4 significant figures.

By writing each number correct to 1 significant figure, work out an estimate for .
You must show all your working.

The length,  cm, of a line is 18.3 cm, correct to the nearest millimetre.  

Complete this statement about the value of .  

  .................... ....................

Ella’s height is 175 cm, correct to the nearest 5 cm.  

Write down the upper bound of Ella’s height.  

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

An equilateral triangle has sides of length 15 cm, correct to the nearest centimetre.
Calculate the upper bound of the perimeter of this triangle.  

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

The length of the side of a square is 12 cm, correct to the nearest centimetre.

Calculate the upper bound for the perimeter of the square.

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

Jo measures the length of a rope and records her measurement correct to the nearest ten centimetres.
The upper bound for her measurement is 12.35 m.

Write down the measurement she records.

.............................................m

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]

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

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]

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]

correct to the nearest whole number.
correct to the nearest whole number.

Work out the upper bound for the value of

, correct to the nearest whole number.
, correct to the nearest whole number.
Work out the upper bound for the value of .

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

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