24
Subtracting (43 − 7)
Textbook: Part 1, lesson 23, pp. 50–51
GoalSubtract down to the ten first, then subtract the rest (43 − 7).
New words
whole ten · yaxlit o‘nlikdoll · qo‘g‘irchoqtoy · o‘yinchoqpoints (score) · ball
Explanation
In 43 − 7 we split the subtrahend: 7 = 3 + 4. First 43 − 3 = 40, then 40 − 4 = 36. So we first go down to the whole ten and then subtract the remaining part.
Worked examples
52 − 6 = (52 − 2) − 4 = 50 − 4 = 46.
71 − 9 = (71 − 1) − 8 = 70 − 8 = 62.
Class activity
“Jumping back”: on a number line children jump back 3 from 43 (to 40) and then 4 more. Each pair chooses a different sum.
Practice
1
77 − 8 = ?
69
2
64 − 9 = ?
55
3
A shop has 45 dolls; 8 of them can talk. How many ordinary dolls are there?
37
4
Said scored 25 points and Nigora scored 7 fewer. How many points did Nigora score?
18