Year 6 Maths reasoning (SATs): Metric units of length, mass and capacity
Part of the Year 6 Maths reasoning (SATs) measures in context chapter. Chapter overview · whole chapter on one page
Metric units of length, mass and capacity
Rule
Length: 10 mm = 1 cm, 100 cm = 1 m, 1000 m = 1 km. Mass: 1000 g = 1 kg. Capacity: 1000 ml = 1 litre.
Changing to a smaller unit gives a bigger number: multiply. Changing to a bigger unit gives a smaller number: divide.
Key ideas
- Smaller unit: multiply. Bigger unit: divide.
- 1 kg = 1000 g, so 2.5 kg = 2500 g.
- Check the answer: a bigger unit should give a smaller number.
Method. Find the number of smaller units in one bigger unit, then multiply or divide.
- Find how many m make one km. There are 1000 m in 1 km.1 km = 1000 m
- Multiply by 1000. Changing to a smaller unit needs more of them, so the number gets bigger: multiply.2.5 x 1000 = 2500
- Write the answer with the new unit. Keep the same measure, in the new unit.2500 m
- Write the answer. 2500 m
Check. 2500 m is the same length, mass or volume as 2.5 km. ✓
Watch out. Going from a bigger unit to a smaller one makes the number bigger.
Method. Find the number of smaller units in one bigger unit, then multiply or divide.
- Find how many g make one kg. There are 1000 g in 1 kg.1 kg = 1000 g
- Divide by 1000. Changing to a bigger unit needs fewer of them, so the number gets smaller: divide.4500 / 1000 = 4.5
- Write the answer with the new unit. Keep the same measure, in the new unit.4.5 kg
- Write the answer. 4.5 kg
Check. 4.5 kg is the same length, mass or volume as 4500 g. ✓
Watch out. Going from a bigger unit to a smaller one makes the number bigger.
Method. Find the number of smaller units in one bigger unit, then multiply or divide.
- Find how many ml make one l. There are 1000 ml in 1 l.1 l = 1000 ml
- Multiply by 1000. Changing to a smaller unit needs more of them, so the number gets bigger: multiply.0.75 x 1000 = 750
- Write the answer with the new unit. Keep the same measure, in the new unit.750 ml
- Write the answer. 750 ml
Check. 750 ml is the same length, mass or volume as 0.75 l. ✓
Watch out. Going from a bigger unit to a smaller one makes the number bigger.
Watch out
Watch out. 0.5 km is 500 m, not 50 m. Move the decimal point the right number of places.
Exam tip
Practice guide. Write both units in the question first, then decide whether to multiply or divide.
Exercise 4A Practice: metric units
Non-calculatorMethod. Find the number of smaller units in one bigger unit, then multiply or divide.
- Find how many cm make one m. There are 100 cm in 1 m.1 m = 100 cm
- Multiply by 100. Changing to a smaller unit needs more of them, so the number gets bigger: multiply.1.199999999999999955591079015 x 100 = 119.9999999999999955591079015
- Write the answer with the new unit. Keep the same measure, in the new unit.119.9999999999999955591079015 cm
- Write the answer. 119.9999999999999955591079015 cm
Check. 119.9999999999999955591079015 cm is the same length, mass or volume as 1.199999999999999955591079015 m. ✓
Watch out. Going from a bigger unit to a smaller one makes the number bigger.
Method. Find the number of smaller units in one bigger unit, then multiply or divide.
- Find how many ml make one l. There are 1000 ml in 1 l.1 l = 1000 ml
- Divide by 1000. Changing to a bigger unit needs fewer of them, so the number gets smaller: divide.3500 / 1000 = 3.5
- Write the answer with the new unit. Keep the same measure, in the new unit.3.5 l
- Write the answer. 3.5 l
Check. 3.5 l is the same length, mass or volume as 3500 ml. ✓
Watch out. Going from a bigger unit to a smaller one makes the number bigger.
Method. Find the number of smaller units in one bigger unit, then multiply or divide.
- Find how many g make one kg. There are 1000 g in 1 kg.1 kg = 1000 g
- Multiply by 1000. Changing to a smaller unit needs more of them, so the number gets bigger: multiply.2.45000000000000017763568394 x 1000 = 2450.00000000000017763568394
- Write the answer with the new unit. Keep the same measure, in the new unit.2450.00000000000017763568394 g
- Write the answer. 2450.00000000000017763568394 g
Check. 2450.00000000000017763568394 g is the same length, mass or volume as 2.45000000000000017763568394 kg. ✓
Watch out. Going from a bigger unit to a smaller one makes the number bigger.
Method. Find the number of smaller units in one bigger unit, then multiply or divide.
- Find how many cm make one m. There are 100 cm in 1 m.1 m = 100 cm
- Divide by 100. Changing to a bigger unit needs fewer of them, so the number gets smaller: divide.480 / 100 = 4.8
- Write the answer with the new unit. Keep the same measure, in the new unit.4.8 m
- Write the answer. 4.8 m
Check. 4.8 m is the same length, mass or volume as 480 cm. ✓
Watch out. Going from a bigger unit to a smaller one makes the number bigger.
Method. Find the number of smaller units in one bigger unit, then multiply or divide.
- Find how many m make one km. There are 1000 m in 1 km.1 km = 1000 m
- Multiply by 1000. Changing to a smaller unit needs more of them, so the number gets bigger: multiply.0.05999999999999999777955395075 x 1000 = 59.99999999999999777955395075
- Write the answer with the new unit. Keep the same measure, in the new unit.59.99999999999999777955395075 m
- Write the answer. 59.99999999999999777955395075 m
Check. 59.99999999999999777955395075 m is the same length, mass or volume as 0.05999999999999999777955395075 km. ✓
Watch out. Going from a bigger unit to a smaller one makes the number bigger.
Method. Find the number of smaller units in one bigger unit, then multiply or divide.
- Find how many mm make one cm. There are 10 mm in 1 cm.1 cm = 10 mm
- Divide by 10. Changing to a bigger unit needs fewer of them, so the number gets smaller: divide.750 / 10 = 75
- Write the answer with the new unit. Keep the same measure, in the new unit.75 cm
- Write the answer. 75 cm
Check. 75 cm is the same length, mass or volume as 750 mm. ✓
Watch out. Going from a bigger unit to a smaller one makes the number bigger.
Method. Find the number of smaller units in one bigger unit, then multiply or divide.
- Find how many ml make one l. There are 1000 ml in 1 l.1 l = 1000 ml
- Multiply by 1000. Changing to a smaller unit needs more of them, so the number gets bigger: multiply.6.5 x 1000 = 6500
- Write the answer with the new unit. Keep the same measure, in the new unit.6500 ml
- Write the answer. 6500 ml
Check. 6500 ml is the same length, mass or volume as 6.5 l. ✓
Watch out. Going from a bigger unit to a smaller one makes the number bigger.
Method. Find the number of smaller units in one bigger unit, then multiply or divide.
- Find how many g make one kg. There are 1000 g in 1 kg.1 kg = 1000 g
- Divide by 1000. Changing to a bigger unit needs fewer of them, so the number gets smaller: divide.1250 / 1000 = 1.25
- Write the answer with the new unit. Keep the same measure, in the new unit.1.25 kg
- Write the answer. 1.25 kg
Check. 1.25 kg is the same length, mass or volume as 1250 g. ✓
Watch out. Going from a bigger unit to a smaller one makes the number bigger.
Method. Change the litres to millilitres, then divide by 250.
- Change to ml. 1.5 litres = 1500 ml.1500 ml
- Divide. 1500 / 250 = 6 glasses.6
- Write the answer. 6
Check. 6 x 250 = 1500. ✓
Method. Change the mass to grams, then divide.
- Change to grams. 2.4 kg = 2400 g.2400 g
- Divide. 2400 / 150 = 16 cakes.16
- Write the answer. 16
Check. 16 x 150 = 2400. ✓
Method. Test each choice against the question.
- Read what the question asks. Decide what the answer must do or show.
- Test the choice. 1 km is 1000 m, so half a kilometre is 500 m.No, 0.5 km is 500 m fits
- Reject the other choices. Half of 1000 is 500, not 50.Yes, 0.5 km is 50 m do not fit
- Write the answer. No, 0.5 km is 500 m
Check. No, 0.5 km is 500 m is the one that fits. ✓
Method. Test each option.
- Check each option. Test each one against the rule or the calculation.
- Tick the true ones. These are the correct metric facts: 100 cm in a metre and 10 mm in a centimetre.1 m = 100 cm, 1 cm = 10 mm
- Leave the others unticked. These do not match.1 kg = 100 g, 1 litre = 100 ml, 1 km = 100 m are not ticked
- Write the answer. 1 m = 100 cm, 1 cm = 10 mm
Check. Each ticked option is true. ✓
Watch out. 1 kg is 1000 g, 1 litre is 1000 ml and 1 km is 1000 m.
Method. Multiply by 100.
- Multiply. 3.25 x 100 = 325.325 cm
- Write the answer. 325 cm
Check. 325 / 100 = 3.25. ✓
Method. 350 ml is 0.35 litres, so add it to the 2 litres.
- Change ml to litres. 350 / 1000 = 0.35 litres.0.35 litres
- Add. 2 + 0.35 = 2.35 litres.2.35 litres
- Write the answer. 2.35 litres
Check. 2.35 x 1000 = 2350 ml. ✓
Method. Change to the same unit first.
- Change metres to centimetres. 4 m = 400 cm.400 cm
- Divide. 400 / 80 = 5 pipes.5
- Write the answer. Five pipes, because 4 m is 400 cm and 400 / 80 = 5.
Check. 5 x 80 = 400. ✓
Method. Change to the same unit, then add.
- Change 0.8 kg. 0.8 kg = 800 g.800 g
- Add. 800 + 650 = 1450 g.1450 g
- Write the answer. 1450 g
Check. 1450 g = 1.45 kg. ✓
Method. Change litres to millilitres.
- Change 2.4 litres. 2.4 x 1000 = 2400 ml.2400 ml
- Compare. They are the same amount.equal
- Write the answer. 2.4 litres is 2400 ml, so they are the same amount.
Check. 2.4 x 1000 = 2400. ✓