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➕ Adding and Subtracting Measurements

Add and subtract lengths, weights, and amounts — keeping the units the same so the numbers line up.

4
lessons
~15 min
to learn
🔢 Math
subject
Ages 6–12
level
Start the course →

What you’ll learn

  1. Add MeasurementsAdd measurements that share a unit by adding the numbers and keeping the unit.Measurements are added like ordinary numbers, as long as their units match. Add the amounts and keep the same unit, so two lengths in centimetres give an answer in centimetres.
  2. Subtract MeasurementsSubtract measurements that share a unit to find what remains.Subtracting measurements works just like subtracting numbers when the units match. Take the amounts away and keep the unit, so 45 g − 20 g leaves 25 g.
  3. Same Units OnlyRecognise when units must be changed to match before adding or subtracting.The golden rule is that you can only add or subtract measurements with the same unit. If they differ, change one first — for example, 1 m becomes 100 cm — so both units match.
  4. Measurement PracticeSolve everyday problems that add or subtract measurements in matching units.Putting it together, you check the units match, then add or subtract the numbers and keep the unit. This lets you solve real length, weight, and amount problems.

Questions this course answers

What is 24 cm + 15 cm?

Both are in centimetres, so add: 24 + 15 = 39 cm.

What is 45 g − 20 g?

Both are in grams, so subtract: 45 − 20 = 25 g.

When you add measurements, they must be in...?

You can only add measurements that share the same unit.

What is 30 cm + 40 cm?

Both are in centimetres, so add: 30 + 40 = 70 cm.

To add 1 m and 50 cm, you should first change 1 m into...?

1 metre is 100 cm, so change it to match the centimetres first.

A jug holds 60 ml of juice. You pour out 25 ml. How much is left?

Pouring out means subtract: 60 − 25 = 35 ml.

Grounded in trusted sources

  • Khan Academy Kids
  • BBC Bitesize — KS2 Maths
  • Britannica Kids
  • PBS Kids — early math

Every Wunder lesson is built from real, reputable sources — never invented.

Related Math courses

📏Choosing the Right Unit⚖️Comparing Measurements🔢Adding and Subtracting to 20🥧Adding Fractions Past One Whole🍕Adding Fractions with the Same Denominator➕Adding Fractions with Unlike Denominators🍎Addition and Subtraction Word Problems🔷All About 2D and 3D Shapes

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