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Estimating and comparing money

Estimate, compare, and calculate different measures including money in pounds and pence

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What a learner can do afterwards

  • Estimate the length of the classroom in metres
  • Compare 1.5 kg and 1200 g and identify which is heavier
  • Calculate the total cost of 3 items at £2.45, £1.30, and £0.75

The lesson

Sometimes you do not need an exact number, just a sensible guess. That guess is called an estimate. You can estimate length, mass, or money. Once you have real numbers, you can compare them to see which is bigger, or add them up to find a total.

Try it together

Amir looks around his classroom without using a ruler. He pictures how many metre-long strides it would take to cross it and guesses about 8 metres. That guess is close to the real length, so it is a good estimate.

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Pencil2.45Ruler1.3Eraser0.75
The shortest bar is the cheapest item. The eraser costs the least at £0.75.
Good to know

To compare money, look at the pounds first. Whoever has more pounds has more money, even if the pence look bigger. Only compare the pence when the pounds are the same.

Estimate first, then compare pounds before pence, and add pounds and pence together to find a total.

Watch it

Where it sits

Where this leads

Jobs that lean on this skill. Follow one to see everything it is built on.

Then practise

8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.

Estimating and comparing money · Mathematics, ages 8 to 9 · LightMySky