Starting at 0 we can count up in 1000s like this:
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 ...
We add 1000 to the previous number to get the next.
These are the multiples of 1000.
Notice that they all end in 000.
Example
When we count up in 1000s, what comes after 4000?
Answer
Start with a multiple of 1000 that you know.
1000 2000 3000 4000 5000
Example
When we count up in 1000s, what comes before 10000?
Answer
List the multiples of 1000 near 10000.
8000 9000 10000 11000 12000