Negative Numbers
Year 7 🔢 Number Work with negative numbers: ordering, adding, subtracting on a number line.
➖ Negative Numbers
Numbers less than zero are negative. We use a minus sign: −3, −10, −0.5
Think of a thermometer: below 0°C is negative temperature!
➕ Adding & Subtracting
Use a number line! Adding moves RIGHT. Subtracting moves LEFT.
Key Rules
$$-a + b = b - a \qquad a - (-b) = a + b$$Example: −5 + 8 = 3 (start at −5, move 8 right)
Example: −3 − (−4) = −3 + 4 = 1
✖️ Multiplying & Dividing
The sign rules for × and ÷:
Sign Rules
$$+ \times + = + \qquad - \times - = + \qquad + \times - = - \qquad - \times + = -$$ Same signs → Positive. Different signs → Negative.
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Interactive Demonstration — Negative Numbers
➖ Number Line Visualiser
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