Mathematical expressions are a combination of numbers, variables (like x, y, or z), and operators (like +, −, ×, and ÷) that represent a particular value or quantity. For example, 2+3 is a simple mathematical expression. The + is an operator that tells us to add the two numbers together.

The operation in the expression 500×3 is multiplication. When you multiply a number by another, you're essentially adding the first number to itself as many times as the second number.

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