Which equation demonstrates the Multiplicative Identity property?

Which equation demonstrates the Multiplicative Identity property?

• A. a × 1 = a
• B. a × 0 = 0
• C. a × a = a
• D. a × 2 = 2a

Answer: (A)

Multiplicative identity means there is a number that leaves every number unchanged when you multiply by it. For multiplication, that special number is 1. So for any number a, a × 1 = a. This is exactly the equation shown, and it holds for all a in the usual number systems (integers, rationals, reals, etc.). It’s the property that makes 1 the identity element for multiplication. If you test other familiar cases, you’ll see why they don’t express the identity idea: multiplying by zero always gives zero, which is not the original number; multiplying a by itself isn’t true for all a (only true in specific cases like a = 0 or a = 1); multiplying by two just scales the number, it isn’t the element that leaves numbers unchanged.

Multiplicative identity means there is a number that leaves every number unchanged when you multiply by it. For multiplication, that special number is 1. So for any number a, a × 1 = a. This is exactly the equation shown, and it holds for all a in the usual number systems (integers, rationals, reals, etc.). It’s the property that makes 1 the identity element for multiplication.

If you test other familiar cases, you’ll see why they don’t express the identity idea: multiplying by zero always gives zero, which is not the original number; multiplying a by itself isn’t true for all a (only true in specific cases like a = 0 or a = 1); multiplying by two just scales the number, it isn’t the element that leaves numbers unchanged.