Which goes on the right, PLUS or MINUS in a counter feature?

I'm designing a feature where the user can increase or decrease a given number by tapping a PLUS or MINUS button on a mobile app. Both buttons are on the same horizontal orientation. I am unable to find a standard as to which goes on the right. I'm leaning toward putting the PLUS to the right, thinking of number-lines and other affordances of 'increase' tend to go from left to right.