Convert a string to integer in a batch file

I have a variable read from a file:

%var%=13,145

I want to add this value to another value:

set /a %var%=%var%+5

but the result is `13+5`, not `13145+5`.

How can I delete this "," from my string?

Do not add commas.

set var=13145

And also, when assigning a variable, don't place it around `%`

set /a var=%var% + 5 (Or simply set /a var += 5)

Test:

@echo off
set var=13145
set /a var=%var% + 5
echo %var%

Output:

13150

### Update

Another solution is to remove those commas with substitution:

set var=13,145
set /a var=%var:,=% + 5