# Step 2 Unit 4 Key Terms

• Addition Property of Equality: Adding the same number to each side of an equation produces an equivalent expression.
• Constant of Proportionality: The constant value of the ratio of two proportional quantities x and y; usually written y = kx, where k is the constant of proportionality. In a proportional relationship, y = kxk is the constant of proportionality, which is the value of the ratio between y and x.
• Direct Proportion (Direct Variation): The relation between two quantities whose ratio remains constant. When one variable increases the other increases proportionally: When one variable doubles the other doubles, when one variable triples the other triples, and so on. When A changes by some factor, then changes by the same factor: A=kB, where k is the constant of proportionality.
• Division Property of Equality: States that when both sides of an equation are divided by the same number, the remaining expressions are still equal
• Equation: A mathematical sentence that contains an equal sign
• Inequality: A mathematical sentence that contains the symbols >, <, ≥, or ≤.
• Inverse Operation: A mathematical process that combines two or more numbers such that its product or sum equals the identity.
• Multiplication Property of Equality: States that when both sides of an equation are multiplied by the same number, the remaining expressions are still equal.
• Proportion: An equation which states that two ratios are equal.
• Subtraction Property of Equality: States that when both sides of an equation have the same number subtracted from them, the remaining expressions are still equal.
• Term: A number, a variable, or a product of numbers and variables.
• Variable: A letter or symbol used to represent a number or quantities that vary.

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