147
Dividing round numbers
Textbook: Part 4, lesson 137, pp. 46–47
GoalDivide round numbers by dropping the same number of zeros from the dividend and divisor.
New words
dropping zeros · nollarni tashlashthe same number of · teng sondagiin total · jamiteam · jamoa
Explanation
We may drop the same number of zeros from the dividend and the divisor, and the answer does not change. 80 : 10 = 8 : 1 = 8. 400 : 20 = 40 : 2 = 20. 900 : 300 = 9 : 3 = 3. 800 : 40 = 80 : 4 = 20. The important thing is to drop the same number of zeros from both.
Worked examples
600 : 30 = 60 : 3 = 20.
1000 : 500 = 10 : 5 = 2.
Class activity
“Equal zeros”: cards show 500 : 50, 700 : 100… Children cross out the same number of zeros from both numbers with a pencil and divide what is left.
Practice
1
80 : 10 = ?
8
2
400 : 20 = ?
20
3
900 : 300 = ?
3
4
800 : 40 = ?
20
5
1000 : 500 = ?
2
6
80 seats at a tennis court are placed equally in 10 rows. How many seats are in one row?
8
7
There are 100 competitors. If each team has 10, how many teams are there?
10