46
Long division (practice)
Textbook: Part 2, lesson 46, pp. 22–24
GoalLong division when the first digit is smaller than the divisor, and checking by multiplication.
New words
checking · tekshirishincomplete dividend · to‘liqsiz bo‘linuvchithousand · minginverse operation · teskari amal
Explanation
The incomplete dividend must be at least as big as the divisor. In 1 000 : 8 the 1 thousand cannot be divided by 8, so we take the first two digits: 10 hundreds. 10 : 8 = 1 (remainder 2), 20 : 8 = 2 (remainder 4), 40 : 8 = 5. The quotient is 125. Check with the inverse operation: 125 × 8 = 1 000.
Worked examples
2 464 : 7: 24 : 7 = 3 (3 left), 36 : 7 = 5 (1 left), 14 : 7 = 2. The quotient is 352.
Check: 352 × 7 = 2 464.
Class activity
“The checker”: in pairs one child solves an example by long division and the other checks it by multiplying. Then they swap roles.
Practice
1
1 500 : 6 = ?
250
2
3 128 : 8 = ?
391
3
5 292 : 7 = ?
756
4
1 000 : 8 = 125. Check: 125 × 8 = ?
1000
5
7 identical pencils cost 5 600 so‘m. How much does one pencil cost, in so‘m?
800