# Can You Pass This Math IQ Quiz?

EDUCATION

By: Torrance Grey

6 Min Quiz

Image: Alberto Guglielmi/ Blend Images/gettyimages

Math: It's a word to strike fear into the hearts of many. But this much-maligned school subject is actually the mother of all the sciences -- none of them could exist without it -- and it's also very important to everyday life. Let's face it,  America has a double standard when it comes to illiteracy and "innumeracy." No one would be proud of a friend who said, "I hate books; I can barely read, and never do it if I don't have to." Yet we readily give ourselves and other people a pass for not knowing the most basic mathematic concepts, ones that allow us to calculate a 15 percent tip on a restaurant bill or figure out how many gallons of gas we'll need for a road trip.

Where do you fall on this spectrum? To help you figure it out, we've created a quiz covering concepts from high school math classes, mainly algebra and geometry. You won't need a calculator for this one -- and, honestly, shouldn't use one -- though in places a pencil and paper might be handy.

Are you ready to stare down the dragon of your school days, and proudly prove your "numeracy"? Sharpen up your No. 2 pencil and get to it!

# Which of these is a prime number?

A prime number is only divisible by itself and 1. Other prime numbers include 7, 11 and 17. They get rarer the farther you get from zero.

# In its most basic definition, "x" in algebra stands for what?

"X" is an unknown number. In some equations, other letters may be pressed into service as other unknowns -- but "x" is always the first choice. It's where we get phrases like "X factor" or titles like "The X Files."

# If 6x - 9 = 25, what is "x"?

Six times six equals 36, minus 9 is 25. This is pretty simple algebra.

# Which of these is one-third expressed as a decimal?

Technically, the 3s should go on forever. This is because 1 can't be evenly divided by 3. Yet if you're dividing a cake into thirds, you can do it perfectly evenly. (Don't think about this too long; your brain will melt).

# Eighty percent expressed as a fraction is ...

This would be easier to recognize as "8/10," which we could have easily used instead. But they're the exact same thing.

# What is the top number of a fraction called?

Fractions consist of a numerator and a denominator. Fun fact: "denominator" has taken on a meaning in everyday English, in the expression "the common denominator," meaning something that unites seemingly different things or people. "Numerator" has no such casual use.

# In geometry, angles are measured in _____.

"Degree" is a flexible word in the English language. We also use it to measure heat, to put a ranking on academic achievement (a master's degree), and to describe an undefined "certain amount" of something ("If you had even a degree of sympathy ...") And, of course, they're vital to geometry.

# The interior angles of a triangle always measure up to ____ degrees.

You'll find this question on many a basic geometry test. If one angle is 45, and the other is 90, then you know the third angle is 45 degrees.

# Which of these are also measured in degrees?

Circles are perfectly round, but mathematicians think of them as implicitly divided up into any number of angles, from the center to any two points on the circumference. This is how we get compass readings, from 1 degree to 360 (or 0 to 359, if you prefer to count that way).

# A line between any two points on a circle is called a/an _____.

The circle's diameter counts as a chord. The radius does not, because it emanates out from the center point of the circle.

# What is 4 cubed?

"Cubed" is the same way of saying "to the power of 3." 4 times 4 is 16, times 4 again is 64.

# Squares and cubes are part of a system called _______.

Science often deals with very large numbers, and scientific notation makes them easier to manage. For example, in astronomy, it's easier to represent vast distances in light years using 10 and a superscript number than to write it out.

# In scientific notation, the number in superscript is called the ______.

The word "exponent" has been hijacked by people who enjoy superlatives. "This stock is about to take off exponentially!" or "After I started reading Jordan Peterson, I saw exponential growth in my personal life!" Note to everyone: "exponential" does not just mean "a lot."

# In geometry, what is the minimum size of a point?

Euclid said it best: "A point is that which has no part." He meant it was a theoretical concept. Likewise, a "line" in geometry has no specified measurement, either.

# How many points do you need to define a line?

From a single point, you could move off in any direction. But just one other point, and suddenly you've got a line -- you can predict its path indefinitely. Just two points! Like a designer once said, "Simplicity is the ultimate style."

# If one interior angle of a triangle is 75, what is the sum of the other two angles?

We covered this in an earlier question: The sum of the three interior angles of a triangle always add up to 180 degrees. Just wanted to see if you were paying attention!

# A 122-degree angle is an _____ angle.

Angles are classed as "acute" (less than 90 degrees) and "obtuse." Fun fact: Outside math, these words are generalized to mean "sharp" and "dull." At the emergency room, you might be asked if your pain is "acute." In the dating world, if you can't see that someone's just not that into you, you're being "obtuse."

# An angle that is exactly 90 degrees is called a/an ______ angle.

A right angle is a 90-degree angle. It's a vital concept to engineering and architecture.

# What is the maximum an obtuse angle can be?

Once an angle goes past 179 degrees to 180, well, it's a line. Beyond that, and it's an angle from the other direction (it might help to actually draw this on a piece of paper, to visualize it).

# What number does the Greek letter "pi" represent?

The letter "pi" is a number used to determine the circumference or the area of a circle. The one for area is better known: A = pi times r(squared).

# In the equation A = pi times r(squared), what does r stand for?

The radius of a circle is half the diameter. Put another way, it's a line from the center of the circle to any point on the circumference.

# A chord going directly across a circle at its widest point (e.g. 90 to 270) is called the ____.

The diameter is always twice the radius, and therefore can be used to find a circle's area. (Sidenote: If you chose "didjeridoo," wipe that smirk off your face; we know you knew better!)

# When you write 8/10 as 4/5, you are reducing it to what?

The denominator is the key here, not the numerator. 5 is the lowest the denominator can go without being split into a fraction/decimal itself. On the other hand, there are plenty of higher denominators possible -- 20, 40, 100. However, reducing fractions to the lowest common denominator is a more common task in math than raising them to a higher common denominator.

# What is 81 divided by 8 written as a fraction?

8 does not divide into 81 evenly, so the answer could be written either as 10 1/8 or as 10.125. These are the same thing.

# What is 66 percent written as a fraction?

Like one-third, two-thirds would go on forever as a decimal: 0.666666 .... As a fraction, either 2/3 or 66/100 gets as close as you reasonably need to get.

# A divisor is ...

In the simple equation 12 /4 = 3, 4 is the divisor. and 12 is the dividend. This is confusing because in everyday life, a "dividend" is the result of something being divided up: "The original investors shared the dividends."

# Which of the numbers in this list -- 1, 2, 11, 12, 121, 122, 212 -- is the median?

If you picked "219," you were confusing median with "mean," or average. But a median number is just one in the middle of a list. Here, that's 12.

# What number would you divide the sum of this list -- 4, 12, 21, 24, 42 -- by to get the mean?

There are five numbers on the list, so you'd divide the sum by five. Or, put another way: 103 divided by 5 equals 20.6. So 20.6 is the mean, or average, in this list.

# Which of these geometric figures can be described as "a triangle with the top cut off"?

Don't try to slide this definition past a geometry teacher, though. The formal definition is a four-sided polygon with only two parallel sides.

# If x cubed minus 5 equals 22, what is x?

3 times 3 is 9, times 3 again is 27. Subtract 5 from that, and you're left with 22.

# In the number 12.37859, which digit is in the hundredths place?

This confuses new learners: on the left of a decimal point, the first digit represents single numbers, and the next one left of that is the tenths place. But to the right, the first place is the tenths place, and the next one hundredths. So here, 7 is in the hundredths place.

# Which of these is NOT an integer?

Integers are whole numbers, whether positive or negative, and zero. A fraction cannot be an integer.

# A "pie wedge" of area inside a circle, defined by two radii, is called a/an ______.

Frequently borrowed by sci-fi writers, "sector" is part of a circle. It's almost a triangle, but is not, because one side (the part defined by the circle's circumference), is curved.

# What is a number's absolute value?

Whether the distance is positive or negative doesn't matter. That is, 4 and -4 have the same absolute value.