minus-n; 3 Senses

Sense Number 1: subtraction operator in mathematics

Commentary: MINUS[+entity][+symbolic][+notation][+arithmetic][+operator][+subtraction]
NOTE: refers to the visible arithmetic sign "-", not the activity of subtraction (Sense 2)

There is a minus in front of that six-figure number.
Sally got a minus on her A, because of grammatical mistakes.

WordNet 0.0 Sense Numbers: 1

Sense Number 2: the act of subtracting one number from another

Commentary: MINUS[+action][+subtraction][+arithmetic]
NOTE: refers to the act of subtracting, not the arithmetic symbol "-" (Sense 1)

Instead of doing three minuses, add those numbers together and just subtract their total.
Your minus here is incorrect, the remainder is 65.44, not 64.23. (subtraction was wrong)

WordNet 3.0 Sense Numbers: 1

Sense Number 3: a negative quality, a drawback

Commentary: MINUS[+quality][+negative]

His foul language is definitely a minus in the boardroom.
The small bedrooms and busy street are the minuses of this home.
Thee are some minuses to running your own business.

WordNet 0.0 Sense Numbers: 2