Everyday maths for Construction and Engineering 1
Everyday maths for Construction and Engineering 1

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Everyday maths for Construction and Engineering 1

4.2 Using pints and gallons

You might still see the old, imperial units for measuring volume.

  • 20 fluid ounces (fl oz) = 1 pint (pt)
  • 8 pts = 1 gallon (gal)

A pint is a little more than half a litre.

A fluid ounce is about 30 ml.

Some measuring jugs show both metric and imperial units.

Described image
Figure 35 Using metric and imperial units

Example: Buying petrol

You have an old one-gallon can in your shed. You take it to the garage to buy petrol for your lawnmower. About how many litres of petrol can you buy?


A pint is a little more than half a litre, so you can get just over a litre for every 2 pints.

There are 8 pints in a gallon, so you can get just over 4 litres of petrol.

Now try the following activity. Remember to check your answers once you have completed the questions.

Activity 11: Converting between metric and imperial measurements

  1. You are mixing up a quantity of weed killer. The packet says to use a pint of weed killer in a gallon of water. You have only a metric measuring jug. How much water should you use with 1 litre of weed killer?
  1. An old car instruction manual tells you to make one pint of screen wash. You prefer to buy ready mixed screen wash from the garage, where it is sold in bottles of 500 ml. How many bottles do you need to buy to be sure you have enough screen wash for your car?


  1. You know that:
    • 8 pts = 1 gallon (gal)

    So you have to use eight times as much water as weed killer.

    If you use 1 litre of weed killer, you will need 8 litres of water.

  1. A pint is a little more than half a litre, and the bottles of screen wash are 500 ml each. So to make one pint of screen wash, you would need to buy two bottles.


In this section you have learned how to:

  • identify the standard units for measuring volume or capacity
  • measure volume (or capacity)
  • compare metric and imperial measures.

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