95
Multiplying larger numbers by 1
Textbook: Part 3, lesson 89, pp. 38–39
GoalMultiplying any number by 1: the product equals the number itself.
New words
multiplying by 1 · 1 ga ko‘paytirishunknown · noma’lummulti-digit number · ko‘p xonali sonconvenient method · qulay usul
Explanation
1 + 1 + 1 + 1 + 1 = 1 × 5 = 5. When we multiply a number by 1 we get the same number: a × 1 = 1 × a = a. This is true for big numbers too: 553 × 1 = 553.
Worked examples
8 × 1 = 8 and 1 × 9 = 9.
If x × 1 = 6 then x = 6; if 1 × y = 31 then y = 31.
Class activity
“The magic one”: children multiply numbers on cards by 1 (even three-digit numbers) and call out “Nothing changed!”
Practice
1
If x × 1 = 6, then x = ?
6
2
If 1 × y = 31, then y = ?
31
3
264 × 1 = ?
264
4
1 × 907 = ?
907
5
Calculate in a convenient way: 47 + 29 + 53 + 30 = ?
159