Starting at 0 we can count up in 6s like this:
0 6 12 18 24 30 36 42 48 54 60 66 72 ...
We add 6 to the previous number to get the next.
These are the multiples of 6.
Example
When we count up in 6s, what comes after 48?
Answer
Start with a multiple of 6 that you know.
36 42 48 54
Example
When we count up in 6s, what comes before 60?
Answer
List the multiples of 6 near 60.
48 54 60 66 72