Use As A Qualifier
In grading systems (such as examination marks), the plus sign indicates a grade one level higher and the minus sign a grade lower. For example, B− ("B minus") is one grade lower than B. Sometimes this is extended to two plus or minus signs; for example A++ is two grades higher than A.
Positive and negative are sometimes abbreviated as +ve and −ve.
In mathematics the one-sided limit x→a+ means x approaches a from the right, and x→a− means x approaches a from the left. For example, when calculating what x−1 is when x approaches 0, because x−1→+∞ when x→0+ but x−1→ −∞ when x→0−.
Read more about this topic: Plus And Minus Signs