How to find a range of numbers

[Robert_Kulig (Robert)]

Hello everyone.
For two days I have been struggling with a problem like …
How to find a range of numbers.

I thought it would be easy, but not for me.

I searched the forum but found no suggestion

Please help. Thank you in advance.

[Still-learning (1-2-3-4...)]

EDIT:

As i said, it is easy only

[Robert_Kulig (Robert)]

This is it! Works great.
Thanks a lot.