Exercise 3.1
1. Which of the following numbers are divisible by 2, by 3 and by 6? (Enter Yes/No)
| Number | Divisible by 2 | Divisible by 3 | Divisible by 6 |
|---|---|---|---|
| (i) 321729 | |||
| (ii) 197232 | |||
| (iii) 972132 | |||
| (iv) 1790184 | |||
| (v) 312792 | |||
| (vi) 800552 | |||
| (vii) 4335 | |||
| (viii) 726352 |
2. Determine which of the following numbers are divisible by 5 and by 10. Check whether the numbers that are divisible by 10 are also divisible by 2 and 5. (Enter Yes/No)
| Number | Divisible by 5 | Divisible by 10 | Divisible by 2 (if divisible by 10) |
|---|---|---|---|
| (i) 25 | |||
| (ii) 125 | |||
| (iii) 250 | |||
| (iv) 1250 | |||
| (v) 10205 | |||
| (vi) 70985 | |||
| (vii) 45880 |
- Fill the table using divisibility test for 3 and 9:
| Number | Sum of the digits in the number | Divisible by 3 | Divisible by 3 |
|---|---|---|---|
| 72 | |||
| 197 | |||
| 4689 | |||
| 79875 | |||
| 988974 | 9 + 8 + 8 + 9 + 7 + 4 = 45 | Yes | Yes |
4. Make 3 different 3 digit numbers using 1, 9 and 8, where each digit can be used only once. Check which of these numbers are divisible by 9.
5. Which numbers among 2, 3, 5, 6, 9 divides 12345 exactly? Write 12345 in reverse order and test now which numbers divide it exactly?
6. Write different 2 digit numbers using digits 3, 4 and 5. Check whether these numbers are divisible by 2, 3, 5, 6 and 9?
7. Write the smallest digit and the greatest possible digit in the blank space of each of the following numbers so that the number formed are divisible by 3. (i) ? 6724 (ii) 4765 ? 2 (iii) 7221 ? 5
8. Find the smallest number that must be added to 123, so that it becomes exactly divisible by 5?
9. Find the smallest number that has to be subtracted from 256, so that it becomes exactly divisible by 10?