Q1.
11. Sort the following numbers into those that are — (a) divisible by 2 only
Answer
22, 38, 66, 78, 62, 84 and 56 are divisible by 2 only.
A number is divisible by 2 if it is even — that is, if its last digit is 0, 2, 4, 6 or 8. "Divisible by 2 only" means it is even but not divisible by 5, so it must not end in 0.
| Number | Last digit | Divisible by 2? | Divisible by 5? |
|---|---|---|---|
| 22 | 2 | Yes | No |
| 38 | 8 | Yes | No |
| 66 | 6 | Yes | No |
| 78 | 8 | Yes | No |
| 62 | 2 | Yes | No |
| 84 | 4 | Yes | No |
| 56 | 6 | Yes | No |
Why it happens: Jumping 2 at a time from 0 lands you on every even number. None of these seven numbers ends in 0 or 5, so 5-jumps miss them all.