Page 64 - Start Up Mathematics_4

2. Three numbers can be grouped in any order and then multiplied.
For example, 8 × 6 × 9 = (8 × 6) × 9 = 8 × (6 × 9) = (8 × 9) × 6

3. The product of a number and 0 is always 0.
For example, 8 × 0 = 0, 13 × 0 = 0, 193 × 0 = 0

4. The product of a number and 1 is the number itself.
For example, 7 × 1 = 7, 18 × 1 = 18, 204 × 1 = 204
5. The product of a number and a sum is equal to the Quick Tip
sum of the individual products of the addends and This property can also be used
the number. for more than two addends.
For example, 6 × (8 + 5) = (6 × 8) + (6 × 5) For example,
9 × (3 + 7 + 6) = (9 × 3) +
(9 × 7) + (9 × 6)
number addends

EXERCISE 5.2

Tick the correct answer.
(a) Which of the following is incorrect?

(i) 6 × 3 = 3 × 6 (ii) 2 × (7 × 1) = (2 × 1) × (7 × 2)
(iii) 2 × 3 = 2 + 2 + 2 (iv) 6 × (3 + 2) = (6 × 3) + (6 × 2)

(b) Which of these is equal to 12 × 5 + 12 × 4?
(i) 12 × 5 × 4 (ii) 12 + (5 × 12) + 4

(iii) 12 × 5 × 12 × 4 (iv) 12 × (5 + 4)
(c) Which of the following is incorrect?

(i) 9 + 2 = 9 + 1 + 1 (ii) (6 + 0) × 8 = (6 × 8) + (0 × 8)
(iii) 7(4 × 5) = (7 × 4) × 5 × 7 (iv) 4 × 13 = 13 × 4

(d) Which of the following is equal to 11 × 3?
(i) 11 + 11 + 11 (ii) 11 + 11 + 11 + 11 + 11
(iii) 11 + 11 (iv) 11 + 11 + 11 + 11

(e) What is 1 × 499?
(i) 500 (ii) 0 (iii) 499 (iv) 1

Multiplication by Numbers Ending with Zero

Multiplication by tens

To multiply a number by 10, write the number followed by one zero.
For example, 2,368 × 10 = 23,680 4,325 × 10 = 43,250

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