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Basic Algebra Operations

This lesson teachers the correct way to help beginning students Algebra I to learn the official Properties of Equality. 1) Addition Property of Equality: If a = b, then a + c = b + c 2) Subtraction Property of Equality: If a = b, then a - c = b - c 3) Multiplication Property of Equality: If a = b, then a × c = b × c 4) Division Property of Equality: If a = b, then a ÷ c = b ÷ c

CoPilot AI defines each property and why it is needed.

1) Addition Property of Equality If you add the same number to both sides of an equation, the equality remains true.
  • Example: If a = b, then a + c = b + c
  • Why it matters: It helps isolate variables when solving equations.
2) Subtraction Property of Equality If you subtract the same number from both sides of an equation, the equality stays intact.
  • Example: If a = b, then a - c = b - c
  • Use case: Often used to move terms from one side to the other.
3) Multiplication Property of Equality Multiplying both sides of an equation by the same number keeps the equation balanced.
  • Example: If a = b, then a × c = b × c
  • Important note: c must not be zero when solving equations.
4) Division Property of Equality Dividing both sides of an equation by the same nonzero number preserves equality.
  • Example: If a = b, then a ÷ c = b ÷ c
  • Key rule: Never divide by zero — it’s undefined.