Kilometres and millimetres · Usually met around P3
Kilometres
1 km = 1000 m; metres take three digits.
How to do it
Method
1 km = 1000 m; metres take three digits
3 km 50 m = 3000 + 50 = 3050 m
Another way
Side by side
3 and 050 → 3050
In full
Kilometres (km) measure long distances, such as how far it is between two places: 1 km = 1000 m, about a 15-minute walk. To change kilometres to metres, multiply by 1000 and add the metres: 3 km 50 m = 3 × 1000 + 50 = 3050 m. A quick way is to write the two numbers side by side, but the metres always take three digits, with 0s in front if needed: 3 and 050 → 3050. To compare distances, change them to the same unit first. To go back, in 4250 m the last three digits, 250, are metres and the 4 in front is kilometres.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
20 km = □ m
Show the answer and working
Answer: 20000
1 km = 1000 m: 20 × 1000 = 20000.
Example 2
4562 m = □ km □ m
Fill in each box
Show the answer and working
Answer: 4，562
The last three digits are the metres, 562; the 4 in front is kilometres.
Example 3
6 km 60 m is further than 6070 m.
True or false?
Show the answer and working
Answer: False
In metres: 6 km 60 m = 6060 m, then compare with 6070 m.
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