📊 Variables, Expressions, and Substitution

Master the fundamentals of using variables to represent unknown quantities and evaluate expressions by substituting values. **What you'll learn:** - Identify and use variables to represent unknown numbers in mathematical situations - Write and simplify algebraic expressions using variables - Substitute given values into expressions and calculate the result - Evaluate expressions with multiple variables and operations - Apply variables to solve real-world word problems

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Questions in this quiz

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Question 1
Which letter is used to represent an unknown number in the expression $5 + x$ ?
Question 2
If $y = 3$ , then the value of $y + 7$ is ___.
Question 3
Which of the following is an algebraic expression?
Question 4
If $a = 4$ , what is the value of $2a + 3$ ?
Question 5
The expression $x + x + x$ can be simplified as $3x$ .
Question 6
Maria has $m$ marbles. She gives away $5$ marbles. Which expression represents how many marbles she has left?
Question 7
If $b = 2$ and $c = 6$ , then $3b + c = ___.
Question 8
Which expression correctly represents "a number $n$ multiplied by $4$ , then decreased by $9$ "?
Question 9
If $x = 5$ , what is the value of $x^2 + 2x$ ?
Question 10
A rectangle has length $l = 8$ cm and width $w = 5$ cm. Using the formula $A = l \times w$ , what is the area?