# Only 20% of Adults Can Pass This 8th-Grade Math Test. Can You?

By: Jouviane Alexandre
2 min
Image: shutterstock

You might be smarter than a 5th-grader, but what about an 8th-grader? Y will always equal mx+b, but will A2 + B2 always equal C2 ? How many degrees are there in a triangle? Can a parallelogram be isosceles? If you’re rolling your eyes at these questions, there’s a big chance that you’re a math genius – or at least smarter than an 8th-grade math student!

8th grade might’ve been 10, 20, 30, or even 40 years ago for you, but there are just some things you’ll never forget! That guy, Pythagoras, might still be your best friend. When someone brings up a slope, you’re probably thinking that it’s equal to ‘m’ versus a skiing trip. If words and phrases like scientific notation, Pythagorean theorem, and plotting coordinates ring a bell, you’re in the right place. You might even be running for a pencil and graphing paper!

A 13- or 14-year-old math student would know the difference between similar figures and similar triangles. They’d be able to find the distance between two points. They’d even be able to find the missing angle of a line, triangle or circle. Can you?

Only 20% of adults can pass this 8th-grade math test. Are you one of them? Can you settle the score against a group of teenagers? Pythagoras is watching!

What is the square root of 169?
4
11
13
16

There are a bunch of perfect squares that you might remember from middle school. To find them, you'd take the number and multiply it by itself. 13 times 13 is equal to 169 making the square root of 169 equal to 13.

Express the following number in scientific notation: 71,200
7.12 x 10^2
7.12 x 10^3
7.12 x 10^4
7.12 x 10^5

When it comes to scientific notation, the answer comes from how many times the decimal moves. If the decimal moved to the right, the exponent will be negative. If it moved to the left, the exponent will be positive. In this example, the (invisible) decimal moved from after the second zero to after the seven, making the answer 7.12 x 10^4.

Evaluate the following expression: 6a + b^2 when a=2, b=2
12
16
20
24

When evaluating an expression, all you must do is fill in the variables. Six times two is equal to 12. Two squared is equal to four. You would then add 12 and 4 to get the answer of 16.

Simplify the following expression: 5a^2 - 9b + 2a^2 - b
3a^2 - 8b
7a^2 - 8b
7a^2 -10b
3a^2 - 10b

With this type of question, it is necessary for you to add like terms. First you must add the terms with a^2. You have 5 and 2 which will give you 7a^2. Then move on to b. You have NEGATIVE 9b and then you proceed to subtract another b which will give you -10b. This makes the correct answer 7a^2 -10b.

Solve the following equation: (x/6) - 3 = -9
-24
36
24
-36

For this equation, you'd start by adding 3 to both sides of the equation. You're left with (x/6) = -6. You'd then multiply both sides of the equation by 6 to get rid of the denominator. This leaves you with x = -36.

What is the approximate volume of a cylinder with radius = 1, height = 4. Volume = (pi)(r^2)(h).
32
12
48
16

For this solution, you'd plug in variables into the equation. One squared is one and when multiplied by 4, you'd get four. Pi is 3.14 so multiplying this by four, you'd get the EXACT answer of 12.57, but by just multiplying by 3, you'd get the approximate answer of 12.

In a straight line, if one angle is equal to 68, what is the other angle equal to?
292
100
112
22

If there are 180 degrees in a straight line and one angle is given to you, you would then need to subtract from 180. With a given angle of 68 degrees, this would make the missing angle 112.

What is the square root of (5/320)?
2/3
3/4
1/8
1/5

When dealing with this kind of question, it is necessary to simplify first. 5 and 320 share a common factor and that's 5. You would first divide the entire expression by five leaving you with the square root of (1/64). Luckily for you, both of these are perfect squares! The square root of 1 is 1 and the square root of 64 is 8 leaving you with the answer of 1/8.

Write the following expression is scientific notation: 0.00295
2.95 x 10^3
2.95 x 10^-3
2.95 x 10^-4
2.95 x 10^4

When it comes to scientific notation, the answer comes from how many times the decimal moves. If the decimal moved to the right, the exponent will be negative. If it moved to the left, the exponent will be positive. In this example, the decimal moved three places to the right which means your exponent would be negative three.

Simplify the following expression: (a/8) x (8/b)
8a +8b
a/b
8a x 8b
8a/8b

When your teacher tells you to simplify, that means to the highest degree. Although (a/8) x (8/b) IS equal to 8a/8b, when asked to simplify, your answer would be wrong. This expression can still be simplified because the eights in the numerator and denominator cancel each other out, making the answer (a/b).

Solve the following equation: (x+2) / 5 = 6
x = 10
x = 28
x = 14
x = 36

When given this equation, you're dealing with two steps. First, you must get rid of the denominator and to do this, you would multiply both sides of the equation by 5. This would leave you with x + 2 = 30. You would then subtract two from both sides, leaving you with the answer, x = 28

For the function f(x) = 5x - 2, what is f(4)?
12
18
10
22

For this function, you would replace 4 where x is. This would give you 5(4) - 2. Thus, the answer is for f(x) = 5x - 2, f(4) = 18.

What is the approximate volume of a cone with a radius of 2 and a height of 6? Volume = (pi)(r^2)(h/3).
~36
~10
~52
~24

When dealing with this type of question, all you have to do is plug in the numbers, and you're lucky we gave you the equation! The radius of 2 (squared) is equal to 4. When the height (6) is divided by three, you'd get 2. Now you have (pi) x 4 x 2. When you multiply three (approximately) by 8, you'd get 24. The exact answer would be 25.13.

If you have a deck of cards, what is the probability that you'd select a 10 as your first card?
1/5
1/8
1/52
1/13

When dealing with the probability in a card deck, you must first remember that there are 52 cards. There are also four 10 cards in each deck. That means 4 out of 52 cards in a deck are a 10, meaning on your first try, there's a 4 out of 52 chance the card you draw will be a 10. This can be simplified down to 1/13.

Evaluate the following expression: 2^3 + 3^3
15
21
35
42

When evaluating these expressions, you must tackle them separately and then add. 2^3 is equal to 8. 3^3 is equal to 27. You would then add 8 and 27 and get your answer of 35.

Rewrite the following expression as a single exponent: 5 x 5^3
5^3
5^8
5^5
5^4

When you are multiplying exponents with the SAME base, you'll be told to keep the base and add the exponents. This means that the base will stay the same and all you have to do is add the exponents together. In this question, the exponent of the first 5 is 1 (although it isn't written). Any number by itself can be said to be held to the exponent of 1. This would make your base, five, and the exponents for your addition 1 and 3. This will give you the solution of 5^4.

Girl Scout Troop #613 sold a record low of Trefoil cookies. What is the mean of the number boxes sold?%0D2, 10, 12, 11, 10, 5, 6, 8
9
10
7
8

In this problem, in order to find the mean, you would add the total of numbers and then divide by the amount of values. When added, this data set gives you a sum of 64. Since there are 8 values, you would divide this sum by 8 to give you the mean (or average) of 8.

Girl Scout Troop #613 sold a record low of Trefoil cookies. What is the median of the number boxes sold?%0D2, 10, 12, 11, 10, 5, 6, 8 OR 2, 5, 6, 8, 10, 10, 11, 12
12
11
10
9

When one needs to find the median, it is imperative that the data set is in numerical order. Then, you must take the middle number. Since this is an even data set, the two numbers in the middle must be averaged. With 8 and 10, we are given a sum of 18. When divided by 2, we get that the median of this data set is 9.

Girl Scout Troop #613 sold a record low of Trefoil cookies. What is the mode of the number boxes sold?%0D2, 10, 12, 11, 10, 5, 6, 8
10
2
11
8

When calculating the mode, it is the number that appears the most within the data set. In this occurrence, the mode would be 10 because it appears twice.

What is the square root of 121?
11
9
14
15

While you might not remember now, the perfect squares are definitely something you once had to memorize! 121 is a perfect square because 11 x 11 would give you this sum.

Express the following in standard notation: 6.5 x 10^2
6,500
.065
650
65

When dealing with standard notation, we are reversing from scientific notation. Since we are given 6.5 x 10^2, in order to revert to standard notation, we must move the decimal to the right twice. This would give us the answer of 650.

Evaluate the following expression: 3ab when a=3, b=3
27
9
256
81

When evaluating expressions, all you must do is substitute the variables. In 3ab, a and b will both be replaced with 3, making the expression 3 x 3 x 3 which will give you the answer of 27.

Simplify the following expression: 2ab^2 - 4a - 6ab^2 + a
-4ab^2 - 3a
4ab^2 + 5a
4ab^2 - 3a
-4ab^2 + 5a

When simplifying these expressions, it is important to pay attention to whether the term is positive or negative. We start off with positive 2ab^2 but it is subtracted by -6 making this coefficient -4. We also have a negative 4a which is combined with 1a, which leaves us with -3a. Hence, the final expression of -4ab^2 - 3a.

Solve the following equation: 3(x+1) = 15
21
9
4
12

In an equation like this, you must first multiply distribute the 3 across (x+1). This leaves you with 3x + 3 = 15. Then you can proceed to subtract both sides by 3 and then divide both sides by three. This will leave you with the answer of x=4.

In a triangle, if two of the angles are 25 degrees each, what is the third angle equal to?
130
155
310
335

If there are two of the same angles in a triangle, this immediately makes it an isosceles. If two angles are 25 degrees and there are 180 degrees in a triangle, that mean you would have x (the remaining angle) = 180 -2(25) which would give you the answer of 130 degrees.

What is the square root of (75/300)?
2/5
1/6
3/8
5/10

When dealing with these expressions, it's not as daunting as you think! First you have to simplify! You want to divide them by a the same number that will make both of them a perfect square. In this care, you'd divide by 3! This will make the numerator 25 and the denominator 100. The square root of (25/100) is the easy answer of 5/10.

Express the following number in scientific notation: 0.0007
7 x 10^4
7 x 10^-3
7 x 10^-4
7 x 10^3

When it comes to scientific notation, the answer comes from how many times the decimal moves. If the decimal moved to the right, the exponent will be negative. If it moved to the left, the exponent will be positive. In this example, the decimal will move four places to the right, which would make the exponent -4.

Simplify the following expression: (1/n-1) / (3/3n-3)
4
3
2
1

When it comes to an expression like this, what you would do first is simplify the right side. (3 / 3n-3) is equal to (1/n-1). This would make the new expression (1/n-1) / (1/n-1). And what do we know about dividing fractions? We can multiply the exponent. When the second fraction is flipped, the (n-1) cancel out and we are left with 1!

Solve the following equation: 4x + 7 = 27
2
3
4
5

This is an easy one! In order to solve for x, what you must do first is subtract 7 from both sides. This leaves you with 4x = 20. You'd then divide both sides by 4 and you're left with x = 5!

For the function f(x) = x^2, what is f(-5)?
10
25
-25
-10

For this function, you must replace f(x) = x^2 with -5. When you take the square of a number, you multiply it by itself twice. When two negatives are multiplied, the product is positive leaving you with the answer of 25.

When drawing from a deck of cards, what is the probability that the first card will be red?
1/13
1/2
1/10
1/3

When it comes to the probability in a deck of cards, you must remember that half of the cards are red and half are black. That means there is a 26/52 chance of drawing a red card. When simplified, you learn that the chances of drawing a red card on the first try is 1 in 2.

Evaluate the following expression: 6^2 / 3^2
9
1
4
2

For this expression, you just have to follow the steps. 6^2 is equal to 36. 3^2 is equal to 9. When 36 is divided by 9, you get 4.

Evaluate the following expression: (x^-3) / (x)
x^-4
x^4
x^-2
x^2

When dealing with dividing exponents with the same base, all you have to do is subtract the exponents. Since you have -4 in the numerator and 1 in the denominator (not written), you would have x^(-3-1) which is x^-4.

In a right triangle, if side a = 3 and side b = 4, what is side c equal to?
12
5
10
9

One of the biggest rules you learned in math was the Pythagorean theorem. For a triangle, a^2 + b^2 = c^2. If side a = 3 and side b is equal to 4, we have 9 + 16 = c^2. This gives us 25 = c^2. To find this answer, you'd have to take the square of both sides which gives you the answer that c = 5! The Pythagorean theorem only works with right triangles, however.

Which of the following numbers isn't a perfect square: 121, 144, 169, 196, 225, 256, 265, 289.
265
256
196
289