Understanding the Minus Sign (−)
The minus sign is one of the most versatile symbols in maths. Depending on context, it carries three distinct meanings.
Three Meanings of the Minus Sign
| Role | Meaning | Example |
|---|---|---|
| Subtraction operator | Subtract right from left | 9 − 4 = 5 |
| Negative sign | Shows a number is below zero | −7 (negative seven) |
| Negation | Reverses the sign of an expression | −(−3) = +3 |
As a Subtraction Operator
15 − 8 = 7 (subtract 8 from 15)
As a Negative Sign
−5 is five units to the left of zero on the number line
Temperature of −12°C means 12 degrees below freezing
As Negation
−(+6) = −6 and −(−6) = +6
In 5 − −3, the first − is subtraction; the second is negative. Result: 5 + 3 = 8.
Key Takeaways
- Between two numbers: minus means subtract.
- In front of a number: minus means negative.
- In front of an expression: minus negates (reverses the sign).
- Two minus signs together become a plus.
Practice Questions
- In 12 − 5 = 7, what role does − play?
- What does −8 mean in the context of temperature?
- Simplify −(−4).
- Calculate 10 − −3.
- Explain the difference between −x and 5 − x.