Which term is defined as the distance from zero on a number line, always positive?

• A. Absolute Value
• B. Surd
• C. Expression
• D. Theorem

Answer: (A)

Think of how far a number lies from zero on the number line. Distance ignores direction, so it’s always nonnegative and is zero only when you’re right at zero. The term that expresses this idea is absolute value, written as |x|. It turns any number into its positive distance from zero: |x| = x if x is nonnegative, and |x| = -x if x is negative. The other terms describe different ideas—surd is a square root that isn’t a whole number, an expression is any combination of symbols, and a theorem is a proven statement. So the distance-from-zero concept that’s always positive is absolute value.