I tried to find an answer to this question but didn't find a clear simple solution.

Assume I have different numbers, for example, 90000, 125784, 547123, 18047.
Now, I need to `ceil` them to a nearest 100k so that they become:

```
90000   =>  100000
125784  =>  200000
547123  =>  600000
18047   =>  100000

```

Looks like a simple task but I have no clue how to make it work for all possible values, from 0 to a billion.