metadata
source: ncert
topic: numbers
class_level: class_7
chapter: ch1
difficulty: beginner
Class 7 | Ch1: Integers Absolute value |a| = distance from zero (always positive). Multiplication: same signs=positive, different signs=negative. (+)×(+)=+, (-)×(-)=+, (+)×(-)=-, (-)×(+)=-. Division: same sign rules as multiplication. (-36)÷(-6)=+6. (-36)÷(+6)=-6. Distributivity: (-7)×8+(-7)×2 = (-7)(8+2) = (-7)(10) = -70. Properties: closure under +,-,×. Commutativity for + and ×. Associativity. a×0=0. Temperature: -3°C fell 5°C = -3+(-5) = -8°C. Common mistake: (-3)^2=+9 but -(3^2)=-9. Two negatives multiply to positive.