13
Subtracting from a round number
Textbook: Part 1, lesson 13, pp. 28–29
GoalLearn subtracting ones from a round number (50 − 6).
New words
subtracting from a round number · yaxlit sondan ayirishbreaking a ten · o‘nlikni bo‘lishminuend · kamayuvchisubtrahend · ayriluvchi
Explanation
In 40 − 4 there are not enough ones. We swap 1 ten for 10 ones: 4 tens = 3 tens 10 ones. Now 3 tens 10 ones − 4 ones = 3 tens 6 ones = 36.
Worked examples
50 − 6: 5 tens = 4 tens 10 ones; 10 − 6 = 4, so the answer is 44.
70 − 8 = 62; 90 − 1 = 89; 60 − 7 = 53.
Class activity
“With sticks”: each child gets 5 bundles of 10 sticks. They show 50 − 6 by untying one bundle and taking away 6 sticks.
Practice
1
90 − 1 = ?
89
2
60 − 7 = ?
53
3
30 − 3 = ?
27
4
Rustam scored 20 goals and Asad scored 3 fewer. How many did Asad score?
17