Grade 8 Math Quiz Review

Simplification of Liketerms: The expression $3x + 5x - 2x$ simplifies to $6x$ .
Solving Single-Variable Equations: For the equation $x + 7 = 15$ , the value of $x$ is $8$ .
Order of Operations: Simplifying the expression $4(3 + 2)$ involves adding the bracketed terms first to get $4(5)$ , resulting in $20$ .

Multiplication: The calculation of $15 \times 8$ results in $120$ .
Percentage Calculation: $25\%$ of $200$ is calculated as $50$ .
Fraction to Decimal Conversion: The fraction $\frac{3}{4}$ is equivalent to the decimal value $0.75$ .

Area of a Rectangle: For a rectangle with a length of $8\,\text{cm}$ and a width of $5\,\text{cm}$ , the area is $40\,\text{cm}^2$ .
Triangle Interior Angles: In a triangle with known angles of $50^\circ$ and $60^\circ$ , the third angle is $70^\circ$ , based on the triangle sum theorem ( $180^\circ$ total).
Perimeter of a Square: Given a square with a side length of $7\,\text{cm}$ , the perimeter is calculated as $4 \times 7\,\text{cm} = 28\,\text{cm}$ .