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Minus — Definition, Formula & Examples

Minus is the word and symbol (−) used to show subtraction, meaning you take one number away from another. For example, "9 minus 4" means start with 9 and take away 4.

The term "minus" denotes the binary operation of subtraction, represented by the symbol −, where the second operand (the subtrahend) is removed from the first operand (the minuend) to produce a result called the difference.

Key Formula

a−b=ca - b = c
Where:
  • aa = The minuend — the number you start with
  • bb = The subtrahend — the number being taken away
  • cc = The difference — the result of the subtraction

How It Works

When you see the minus sign between two numbers, subtract the second number from the first. In the expression a−ba - b, you start with aa and remove bb. The result is called the difference. The minus sign can also appear in front of a single number, like −5-5, to indicate a negative value.

Worked Example

Problem: What is 15 minus 8?
Write the expression: Use the minus sign to set up the subtraction.
15−815 - 8
Subtract: Start at 15 and take away 8.
15−8=715 - 8 = 7
Answer: The difference is 7.

Why It Matters

Subtraction is one of the four basic operations you use throughout all of math, from balancing a budget to solving algebra equations. Recognizing the minus sign and knowing how it works is essential before moving on to topics like negative numbers and equation solving.

Common Mistakes

Mistake: Thinking order doesn't matter: assuming 5−35 - 3 is the same as 3−53 - 5.
Correction: Unlike addition, subtraction is not commutative. 5−3=25 - 3 = 2, but 3−5=−23 - 5 = -2. Always subtract in the order given.

Related Terms

  • Difference — The result you get when using minus
  • Arithmetic — The branch of math that includes subtraction
  • Product — Result of multiplication, another basic operation
  • Quotient — Result of division, another basic operation
  • Formula — Expressions that often include minus signs