Rounding, Estimation & Error Intervals (Edexcel GCSE Maths: Foundation)

A number  is rounded to 2 significant figures.
The result is 0.78.

Write down the error interval for .

Work out an estimate for  

A train is travelling at a speed of 124 miles per hour.

Work out an estimate for the number of seconds that the train takes to travel 1 mile.

Is your answer to part (a) and overestimate or an underestimate? Give a reason for your answer.

By writing each number correct to 1 significant figure, estimate the value of

You must show all your working.

The height, metres, of a tower is 76.3 m, correct to 1 decimal place.
Complete this statement about the value of .

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

By rounding each number correct to 1 significant figure, estimate the value of

You must show all your working.

Calculate 

Give your answer correct to 4 decimal places

By rounding each number correct to 1 significant figure, show that an estimate for this calculation is 20.

Write 0.047883 correct to 2 significant figures.

Write 6.8167 correct to 3 significant figures.

The amount of fuel, litres, in a boat’s fuel tank is 135 litres, correct to the nearest litre.

Complete the statement about the value of .

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

Marco watched 25 boats enter a port, of which 9 had a mast. There are a total of 200 boats in the port.

Calculate an estimate of the number of boats in the port that have a mast.

Simone used her calculator to work out the value of a number .

The answer on her calculator began

                                                                  11.8

Complete the error interval for .

Alfie and Bryony use a calculator to work out 

Alfie's answer is 47.493
Bryony's answer is 4.749

One of these answers is correct.

Use approximations to find out which answer is correct.

Jonah wants to build a tower out of matchsticks.
He wants to build the tower so that it is the same height as the room, which is 394.5 cm high.

Jonah knows that he can increase the height of the tower by 3.8 cm each hour.
He plans to spend 5 hours building the tower each day.

Estimate how many days it will take Jonah to complete his tower.

Jonah learns a new building technique.
The rate at which he can increase the height of the tower per hour by increases.

How does this affect your answer to part (a)?

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 .

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

The length, cm, of a sheet of paper is 29.7 cm, correct to the nearest millimetre.

Complete this statement about the value of .

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

The mass, grams, of a banana is 115 g, correct to the nearest 5 g.

Complete the statement about the value of .

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

By rounding each number correct to 1 significant figure, estimate the value of 

You must show all your working.

The amount of water,  litres, in a jug is 1.5 litres, correct to the nearest 0.1 litre.

Complete this statement about the value of .

The length, cm, of a pencil is 9.8cm, correct to 2 significant figures.

Complete the statement about the value of  .

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

The length of a truck, metres, is 8.2m, correct to 1 decimal place.
Complete this statement about the value of.

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

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

Zach goes on holiday.

The mass, kilograms, of his suitcase is 23.5 kg, correct to the nearest 500 g.
Complete this statement about the value of .

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

Write 0.046875 correct to 2 significant figures.

Without using a calculator, estimate, by rounding each number correct to 1 significant figure,

You must show all your working.

The width,  metres, of a room is 4.2 metres, correct to the nearest 10 centimetres.

Complete this statement about the value of .

..............  ..............

The length,  metres, of a garden is 78.5 metres, correct to the nearest half metre.

Complete this statement about the value of .

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