making JavaScript math logic ; or another programming language that's recommended

Hey guys it's my first time here !

I would really appreciate any answers , just anything !
It's okay to just give me the logic mapping or another programming language that can do this.

So i got this problem on my project

Input_1 : start value
Input_2 : end value
Range 0-10 ; output 1 each increase
Range 11-20 ; output 2 each increase
Range 21-30 ; output 3 each increase
Range 31-40 ; output 4 each increase

So when i input
Start : 9 , end : 11 it should print 3 (1+2)

At first i used if and double && but it only works between two range like the example above ; if i input something that contains 3 range like 9-22 ; thebif doesn't work anymore.

So yeah , I maybe asking too much but any help will be appreciated !

Or share this problem maybe someone knows how.
Thanks !

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