Calculating with measures – Grade 5
Convert length, mass and time: add matching units and distinguish factors of 100 from 60. Create a free worksheet or try an online test.
🎯 What you will learn
- ✓Match units before adding
- ✓Convert time differently from length
💡 How it works
A measurement has a number and a unit. 3 m and 3 cm use the same number but represent very different lengths.
How it works
💡 Convert to the same unit first: 1 m = 100 cm; 1 kg = 1000 g; 1 h = 60 min.
Moving to a smaller unit makes the number larger: 2 m is 200 cm. Moving back makes it smaller: 3500 g is 3.5 kg. The actual length or mass stays unchanged.
Convert each part of a mixed measurement: 2 m 35 cm = 235 cm. Time uses a different factor: 1 h 30 min is 90 min, not 130. Write the conversion factor beside your calculation first.
🧩 See the method
✍️ Worked examples
Worked examples 1
2 m 35 cm + 80 cm
- 1.2 m = 200 cm; 200 + 35 = 235 cm.
- 2.235 + 80 = 315 cm.
- 3.315 cm is 300 cm plus 15 cm.
✓ 315 cm = 3 m 15 cm
Worked examples 2
1 h 25 min + 50 min
- 1.1 h = 60 min; 60 + 25 = 85 min.
- 2.85 + 50 = 135 min.
- 3.135 = 2 × 60 + 15: two hours and 15 minutes.
✓ 135 min = 2 h 15 min
⚠️ Common mistakes
- • Writing 2 m + 35 cm as 37 cm. Convert the metres first.
- • Treating an hour as 100 minutes. Use a factor of 60 here.
📝 Try it yourself
1.
3 m = ? cm
Show answer
300
2.
2 kg 400 g = ? g
Show answer
2400
3.
450 cm = ? m
Show answer
4,5
4.
2 h 10 min = ? min
Show answer
130
5.
1 kg − 250 g = ? g
Show answer
750
6.
95 min = ? h ? min
Show answer
1 h 35 min
Create matching questions
Create a compact printable worksheet or start an online test.
Learn next
FAQ
Is 1.5 hours 1 hour 5 minutes?
No. 0.5 hours is half an hour, or 30 minutes. The total is 90 minutes.
Can I add metres and kilograms?
No. Length and mass are different kinds of measurement. Only matching quantities can be added this way.