10 Most Common 8th Grade Common Core Math Questions

B. \(20 π\)

C. \(36 π\)

D. \(80 π\)

8- What is the area of an isosceles right triangle that has one leg that measures 6 cm? _________

9- A taxi driver earns $9 per 1-hour work. If he works 10 hours a day and in 1 hour he uses 2 liters of petrol at a price $1 per 1-liter. How much money does he earn in one day?

A. $90

B. $88

C. $70

D. $60

10- What is the solution of the following system of equations?
\(\frac{-x}{2}+ \frac{y}{4} = 1\)
\(\frac{-5y}{6}+ 2x = 4\)

A. \(x=48,y=22 \)

B. \(x=50,y=20\)

C. \(x=20,y=50\)

D. \(x=22,y=48\)

Best 8th Grade Common Core Math Prep Resource for 2026

5 Full-Length Common Core Grade 8 Math Practice Tests The Practice You Need to Ace the Common Core Math Test

Download

$27.99 Original price was: $27.99.$17.99Current price is: $17.99.

Rated 4.47 out of 5 based on 217 customer ratings

Satisfied 209 Students

Answers:

2- B
Use the area of rectangle formula \((s = a × b)\).
To find the area of the shaded region subtracts smaller rectangle from the bigger rectangle.
\(S_{1} – S_{2} = (10 ft × 8ft) – (5ft × 8ft) ⇒ S_{1} – S_{2} = 40ft\)

The Ultimate Algebra Bundle From Pre-Algebra to Algebra II

Download

$109.99 Original price was: $109.99.$54.99Current price is: $54.99.

3- B
Use the formula for Percent of Change
\(\frac{New \space Value-Old \space Value}{Old \space Value}× 100 \%\)
\(\frac{28-40}{40}× 100 \% = –30 \% \)(negative sign here means that the new price is less than old price).

4- C
Use the simple interest formula:
I=prt
(I = interest, p = principal, r = rate, t = time)
\(I=(5000)(0.05)(4)=1000\)

5- 8
Use the formula of a rectangular prism.
\(V = (length) (width) (height) ⇒ 2000 = (25) (10) (height) ⇒
height = 2000 ÷ 250 = 8\)

6- B
Use this formula: Percent of Change
\(\frac{New \space Value-Old \space Value}{Old \space Value}× 100 %\)
\(\frac{16000-20000}{20000}× 100 % \)
\(= 20 \% \space and \space \frac{12800-16000}{16000}× 100 \% = 20 \%\)

7- B
To find the area of the shaded region, subtract the smaller circle from the bigger circle.
\(S_{bigger}-S_{smaller} =π(r_{bigger})^2 -π(r_{smaller})^2⇒S_{bigger}-S_{smaller}=π(6)^2-π(4)^2\)
\(⇒ 36 π – 16π = 20 π\)

8- 18
\(a = 6 ⇒\) area of the triangle is:
\(\frac{1}{2}(6×6)=\frac{36}{2}=18 \space cm^2\)

9- C
\($9×10=$90\)
Petrol use: \(10×2=20 \space liters\)
Petrol cost: \(20×$1=$20\)
Money earned: \($90-$20=$70\)

10- D
\(\frac{-x}{2}+ \frac{y}{4} = 1\)
\(\frac{-5y}{6}+ 2x = 4\)
Multiply the top equation by 4. Then,
\(-2x+ y = 4\)
\(\frac{-5y}{6}+ 2x = 4\)
Add two equations.
\(\frac{1}{6}y=8→y=48\), plug in the value of y into the first equation →\(x=22\)

Looking for the best resource to help you succeed on the 8th Grade Common Core Math test?

The Best Books to Ace the 8th Grade Common Core Math Test

5 Full-Length Common Core Grade 8 Math Practice Tests The Practice You Need to Ace the Common Core Math Test

Download

$27.99 Original price was: $27.99.$17.99Current price is: $17.99.

Rated 4.47 out of 5 based on 217 customer ratings

Satisfied 209 Students