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Solving money measurement and time problems

Model real-world problems involving measurement, money, and time by choosing appropriate representations and interpreting results in context

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What a learner can do afterwards

  • Choose whether to use a bar model, number line, or equation for a measurement problem
  • Model a multi-step money problem with equations and interpret the final answer as change or total cost
  • Create a line plot from measurement data and use it to answer questions about the real-world situation
  • Choose a bar model, number line, or equation to model a money problem.

1 · Read

A number line shows an amount increasing or decreasing. Bars placed side by side help compare amounts. A bar split into parts can show cost and change. An equation records the calculation. Choose the model that shows the numbers you need, then say what the answer means.

Try it together

Mia buys a book for $12 and a pencil case for $5. First she adds the costs: 12 + 5 = 17. She pays with a $20 bill, so she finds the change: 20 minus 17 equals 3. Mia gets $3 back.

151617181920+$3

Use one money unit throughout a calculation. £1 is 100p, so £2.40 is 240p. To turn pence back into pounds, split off each 100p: 365p is £3.65. Add prices for total cost. For equal prices, multiply price by item count, or add the price once for each item. When payment covers the cost, subtract the total cost from the amount paid to find change.

Line plots put measurements or prices on a scale. Each X stands for one object at that value. Count a stack to find how many share a value. The tallest stack shows the most common value; equal tallest stacks mean a tie.

Length (cm). Each X is one observation. 4: 0 observations; 5: 2 observations; 6: 2 observations; 7: 1 observation; 8: 0 observations.Each X is one observation.45678Length (cm)
This line plot shows five pencils measured in centimeters. Each X is one pencil.
Good to know

If the amount paid is less than the cost, more money is needed. A negative paid-minus-cost result can show how much is still owed. Check which amount the question asks for and include its unit.

Pick the right picture for the problem, solve it step by step, then check that your answer makes sense in real life.

2 · Watch

Take it off screen

Print a worksheetA4 with an answer key page for grown-ups. No screen, no internet.

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.

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Solving money measurement and time problems · Mathematics, ages 7 to 8 · LightMySky