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

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

Calculate.

Give your answer correct to 2 significant figures.

The sides of a square are 15.1 cm, correct to 1 decimal place.

Find the upper bound of the area of the square.

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

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

An equilateral triangle has side length 12 cm, correct to the nearest centimetre.

Find the lower bound and the upper bound of the perimeter of the triangle.
 

Lower bound = ......................................... cm
Upper bound = ......................................... cm

The area of a square is 42.5 cm², correct to the nearest 0.5 cm².
 
Calculate the lower bound of the length of the side of the square.
 

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

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

The sides of an isosceles triangle are measured correct to the nearest millimetre.
One side has a length of 8.2 cm and another has a length of 9.4 cm.

Find the largest possible value of the perimeter of this triangle.

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

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

Work out the upper bound for the value of .

Anna walks 31 km at a speed of 5 km/h.
Both values are correct to the nearest whole number.

Work out the upper bound of the time taken for Anna’s walk.

...................................... hours

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

Work out the upper bound for the value of

Saafia has a barrel containing 6000 millilitres of oil, correct to the nearest 100ml.
She uses the oil to fill bottles which each hold exactly 50ml.
 
Calculate the upper bound for the number of bottles she can fill.