73
Units of length (continued)
Textbook: Part 3, lesson 73, pp. 16–18
GoalThe kilometre: 1 km = 1 000 m; converting between km and m; distance problems.
New words
kilometre · kilometr (km)distance · masofastep, pace · qadamroad, route · yo‘l
Explanation
Long distances, such as between cities or the length of a railway, are measured in kilometres. 1 km = 1 000 m, so 1 km = 10 000 dm = 100 000 cm. When calculating with mixed km and m, change to metres: 2 km 400 m = 2 400 m. The result can be written again as km and m.
Worked examples
5 km 40 m = 5 000 m + 40 m = 5 040 m; 9 600 m = 9 km 600 m.
2 km 400 m + 1 km 850 m = 2 400 m + 1 850 m = 4 250 m = 4 km 250 m.
Class activity
“Route”: on a class map, children estimate the distance between two cities of Uzbekistan, then split it into parts and add the parts in km and m.
Practice
1
6 km 25 m = ? m
6025
2
3 km = ? dm
30000
3
It is about 300 km from Tashkent to Samarkand. A train has gone 185 km. How many kilometres are left?
115
4
The way from school to home is 2 km 350 m. Aziza goes to school and back. How many metres does she walk in 5 days?
23500
5
A child’s step is 50 cm. How many metres are 4 000 steps?
2000