Page 105 - Start Up Mathematics_4

(b) Factors of 15 = _____________________

Factors of 36 = _____________________
Common factors of 15 and 36 = _____________________

5. Is 246 a multiple of 8?
6. Which of the numbers 84, 96, 215, 320, 306, 400, 825 are divisible by the given
numbers?

(a) 2 (b) 3 (c) 5 (d) 10
7. Write all the prime numbers between 10 and 30.

8. Express (a) 90 (b) 117 as the product of their prime factors.

9. Write the first five even multiples of 4.
10. Write the first five odd multiples of 11.

SCRATCH YOUR BRAIN

1. What is the least number that should be added to 8,345 to make it divisible by 3?
(Hint: Add the digits and find the least number to be added.)

2. What is the least number that should be added to 6,148 to make it divisible by both
3 and 10?
(Hint: Add the digits and find the least number which when added is divisible by 3
and has 0 at its unit place.)

3. What is the least number that should be subtracted from 9,768 to make it divisible by 5?
4. Neena is placing potted plants on the steps of her school auditorium for a function.
She places a plant on every third step. If the auditorium has 21 steps, how many pots
will she need? Also find the step numbers on which she places the plants.

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