Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Definition of a Variable: A letter (like ) used to represent a number we do not know yet.
Algebraic Expression: A mathematical phrase that contains numbers, operators, and variables (e.g., ), but no equals sign.
Algebraic Equation: A mathematical statement that says two expressions are equal (e.g., ).
Substitution: The process of replacing a variable with a specific number to find the value of an expression.
Translating Words to Math: Turning phrases like '3 more than a number' into or 'twice a number' into .
📐Formulae
(Addition: more than )
(Subtraction: less than )
(Multiplication: times )
(Division: divided by )
💡Examples
Problem 1:
Write an algebraic expression for the following: 'Sarah has stickers and her friend gives her 12 more.'
Solution:
Explanation:
We start with the unknown number of stickers () and add 12 to represent the stickers she received.
Problem 2:
Find the value of the expression if .
Solution:
17
Explanation:
Substitute 5 for : . Following the order of operations, multiply first to get , then subtract 3 to get .
Problem 3:
Solve the simple equation: .
Solution:
Explanation:
To find the unknown , we ask: 'What number added to 7 equals 20?' We can subtract 7 from 20 to find the answer ().