28
Multiplying a multi-digit number by a one-digit number
Textbook: Part 1, lesson 28, pp. 87–89
GoalMultiply a multi-digit number by a one-digit number; calculate with exchange rates.
New words
multi-digit number · ko‘p xonali soncurrency · valyutaexchange rate · valyuta kursidollar · dollar
Explanation
To multiply a multi-digit number by a one-digit number, write the one-digit number under it and multiply each place from right to left, adding the number carried from the previous place. An exchange rate is the value of one unit of a foreign currency in so‘m. To change foreign money into so‘m, multiply the amount by the rate.
Worked examples
4 739 × 6 = 28 434; 52 068 × 7 = 364 476.
Suppose, for example, 1 dollar = 12 600 so‘m. Then 5 dollars = 5 × 12 600 = 63 000 so‘m.
Class activity
“Currency exchange”: children play seller and customer. The board shows “1 dollar = 12 600 so‘m”; the customer wants to change 3, 4 or 9 dollars and the seller works out how many so‘m to give.
Practice
1
3 186 × 5 = ?
15930
2
58 302 × 4 = ?
233208
3
Taking 1 dollar = 12 600 so‘m, work out how many so‘m 7 dollars are.
88200
4
1 euro = 100 euro cents. How many cents are in 46 euros?
4600
5
130 524 × 3 = ?
391572