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Succeed with maths: part 2
Succeed with maths: part 2

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4 Less familiar units

You’ve nearly reached the end of this week but there is one final activity to check your newly honed skills with converting between units. This involves some units that you may not be familiar with. However, all the techniques that you have been building over the last two weeks are still relevant, so bear these in mind as you work your way through Activity 8. Don’t forget to click on ‘reveal comment’ for an additional hint.

Activity 8 Converting between less familiar units

Timing: Allow approximately 5 minutes
  • a.Given the fact that:

    one kWh equals 3 600 000 cap j full stop

    left parenthesis kWh equals kilowatt minus hour comma cap j equals joules and both are units of energy right parenthesis

    Now convert 322 kWh to J.


Remember to consider whether the final answer should be bigger or smaller than the original value given. This will tell you whether to multiply or divide by the conversion factor.


one kWh equals 3 600 000 cap j

This means that for every 1 kWh there are 3 600 000 J. That is a lot of joules for each kilowatt-hour! So the final answer will be much larger than the original value. That means multiplying to convert between the two.

322 kWh equals left parenthesis 322 multiplication 3 600 000 right parenthesis cap j equals 1 159 200 000 cap j

  • b.Given that 1 chain = 66 feet, convert 4345 feet to chains.


  • b.This time the final answer will be smaller than the original value, so you need to divide.

    4345 feet equals left parenthesis 4345 division 66 right parenthesis chains equals 65.83 chains left parenthesis to two decimal places right parenthesis

  • c.Given that: one carat equals 20 mg left parenthesis mg equals milligrams right parenthesis

    convert 3.5 carats to mg.


  • c.The final answer needs to be larger than the original value. This means you must multiply.3.5 carats equals left parenthesis 3.5 multiplication 20 right parenthesis mg equals 70 mg