Year 6 Arithmetic (SATs): Metric length and mass conversions
Part of the Year 6 Arithmetic (SATs) measures and conversions chapter. Chapter overview · whole chapter on one page
Metric length and mass conversions
Rule
Length: 1 km = 1000 m, 1 m = 100 cm, 1 m = 1000 mm, 1 cm = 10 mm.
Mass: 1 kg = 1000 g.
To change to a smaller unit, multiply. To change to a bigger unit, divide. Move the decimal point the same number of places as the zeros.
Key ideas
- Smaller unit: multiply. Bigger unit: divide.
- 3.245 m = 3,245 mm, because there are 1000 mm in 1 m.
- Check the direction: a bigger unit gives a smaller number.
Method. Multiply by 1000, because a millimetre is smaller than a metre.
- Write the conversion fact. 1 m is 1000 mm.1 m = 1000 mm
- Multiply to change to the smaller unit. Each m has 1000 mm, so multiply.3.245 × 1000 = 3245
- Write the answer. 3245 mm
Check. 3,245 ÷ 1000 = 3.245 m. ✓
Watch out. Moving the point three places to the right gives 3,245, not 3.245.
Method. Divide by 1000, because a kilogram is bigger than a gram.
- Write the conversion fact. 1000 g is 1 kg.1000 g = 1 kg
- Divide to change to the bigger unit. Each kg is 1000 g, so divide.4500 ÷ 1000 = 4.5
- Write the answer. 4.5 kg
Check. 4.5 × 1000 = 4,500. ✓
Method. Multiply by 1000, because a metre is smaller than a kilometre.
- Write the conversion fact. 1 km is 1000 m.1 km = 1000 m
- Multiply to change to the smaller unit. Each km has 1000 m, so multiply.2.5 × 1000 = 2500
- Write the answer. 2500 m
Check. 2,500 ÷ 1000 = 2.5 km. ✓
Exercise 8A Practice: metric length and mass
Non-calculatorMethod. Multiply for a smaller unit, divide for a bigger unit.
- Write the conversion fact. 1 m is 100 cm.1 m = 100 cm
- Multiply to change to the smaller unit. Each m has 100 cm, so multiply.3.4 × 100 = 340
- Write the answer. 340 cm
Check. The answer is in cm. ✓
Method. Multiply for a smaller unit, divide for a bigger unit.
- Write the conversion fact. 1 m is 1000 mm.1 m = 1000 mm
- Multiply to change to the smaller unit. Each m has 1000 mm, so multiply.2.75 × 1000 = 2750
- Write the answer. 2750 mm
Check. The answer is in mm. ✓
Method. Multiply for a smaller unit, divide for a bigger unit.
- Write the conversion fact. 1000 m is 1 km.1000 m = 1 km
- Divide to change to the bigger unit. Each km is 1000 m, so divide.5600 ÷ 1000 = 5.6
- Write the answer. 5.6 km
Check. The answer is in km. ✓
Method. Multiply for a smaller unit, divide for a bigger unit.
- Write the conversion fact. 10 mm is 1 cm.10 mm = 1 cm
- Divide to change to the bigger unit. Each cm is 10 mm, so divide.780 ÷ 10 = 78
- Write the answer. 78 cm
Check. The answer is in cm. ✓
Method. Multiply for a smaller unit, divide for a bigger unit.
- Write the conversion fact. 1 kg is 1000 g.1 kg = 1000 g
- Multiply to change to the smaller unit. Each kg has 1000 g, so multiply.0.046 × 1000 = 46
- Write the answer. 46 g
Check. The answer is in g. ✓
Method. Multiply for a smaller unit, divide for a bigger unit.
- Write the conversion fact. 1000 g is 1 kg.1000 g = 1 kg
- Divide to change to the bigger unit. Each kg is 1000 g, so divide.3250 ÷ 1000 = 3.25
- Write the answer. 3.25 kg
Check. The answer is in kg. ✓
Method. Multiply for a smaller unit, divide for a bigger unit.
- Write the conversion fact. 1 kg is 1000 g.1 kg = 1000 g
- Multiply to change to the smaller unit. Each kg has 1000 g, so multiply.1.205 × 1000 = 1205
- Write the answer. 1205 g
Check. The answer is in g. ✓
Method. Multiply for a smaller unit, divide for a bigger unit.
- Write the conversion fact. 1000 mm is 1 m.1000 mm = 1 m
- Divide to change to the bigger unit. Each m is 1000 mm, so divide.6040 ÷ 1000 = 6.04
- Write the answer. 6.04 m
Check. The answer is in m. ✓
Method. Multiply for a smaller unit, divide for a bigger unit.
- Write the conversion fact. 1 km is 1000 m.1 km = 1000 m
- Multiply to change to the smaller unit. Each km has 1000 m, so multiply.0.5 × 1000 = 500
- Write the answer. 500 m
Check. The answer is in m. ✓
Method. Multiply for a smaller unit, divide for a bigger unit.
- Write the conversion fact. 100 cm is 1 m.100 cm = 1 m
- Divide to change to the bigger unit. Each m is 100 cm, so divide.12300 ÷ 100 = 123
- Write the answer. 123 m
Check. The answer is in m. ✓
Method. Change 3.5 m to centimetres, then divide by 7.
- Change to centimetres. 3.5 m = 350 cm.350 cm
- Divide by 7. 350 ÷ 7 = 50.50 cm
- Write the answer. 50 cm
Check. 7 × 50 = 350. ✓
Method. Change the flour to grams, then add.
- Change the flour. 2.5 kg = 2,500 g.2,500 g
- Add. 2,500 + 750 = 3,250.3,250 g
- Write the answer. 3,250 g
Check. 3,250 g = 3.25 kg. ✓
Method. Multiply by 1000 to change km to m.
- Use the fact. 1 km = 1,000 m.1,000 m
- Multiply. 2.5 × 1,000 = 2,500.2,500 m
- Write the answer. No, 2.5 km = 2,500 m, because 1 km is 1,000 m, so multiply 2.5 by 1,000.
Check. 250 m is 0.25 km. ✓