Basic BAT calculator command
I am trying to do a very basic 2 value input BAT file but I am struggling. I used a free template from Wikihow and readjusted but something is not right.
I want to calculate 100/(A/B+1) and I know for a fact that the Batch calculation ignores the "+1" for some reason and basically just calculates "100/(A/B). Please help. Thanks.
TITLE Calculator
ECHO OFF
CLS
:TOP
color 3f
Cls
:SUM
CLS
ECHO 
ECHO[
ECHO Division
ECHO[
ECHO 
ECHO[
set /p A=" Enter First Amount = "
ECHO[
set /p B=" Enter Second Amount = "
SET /A C=100/(A/B+1)
ECHO[
ECHO 
ECHO Result %C%
PAUSE
GOTO:TOP
3 answers

I suspect this is an order of operations issue.
Remember that plus comes after division.
You might need this instead:
SET /A C=100/(A/(B+1))
This will allow the B+1 to come before the division.

SET /A
doesn't ignore the+1
:E.g.
SET /A 100/(10/2+1)
outputs16
; the problem you most likely have is this:Any SET /A calculation that returns a fractional result will be rounded down to the nearest whole integer.
(Source)
However, it is possible to work around this issue:
SETLOCAL EnableDelayedExpansion SET /A "var=100000/(10/2+1)" SET "fraction=%var:~3%" & SET /A "var/=1000" IF !fraction:~1! GEQ 5 SET /A "fraction+=10" SET "fraction=!fraction:~0,1!" ECHO %var%.%fraction%
Basically you multiply the number to be divided by
10^(n)
and  after you set the fraction (%var:~n%
)  divide it by10^(n)
again. Then you check the last digit of the fraction for proper rounding and remove it (read more). 
I am assuming you were looking for:
SET /A B=B+1 SET /A C=100/(A/B)