GRE Math : Arithmetic

Study concepts, example questions & explanations for GRE Math

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Example Questions

Example Question #1 : Operations

Choose the answer which best solves the following equation:

Possible Answers:

Correct answer:

Explanation:

When multiplying integers, if both of the signs of the integers are the same (positive, or negative) then your result will be positive:

First multiply the ones digit of both numbers together. If the product is greater than ten remember to carry the one to the tens place.

Next multiply the ones digit of the smaller number with the tens digit of the larger number and add the number that was carried over.

Combine these two together to get:

Example Question #122 : Integers

Of a group of 335 graduating high school atheletes, 106 played basketball, 137 ran track and field, and 51 participated in swimming. What is the maximum number of students that did both track and field and swimming upon graduation?

Possible Answers:

51

157

55

106

335

Correct answer:

51

Explanation:

Simply recognize that logically, the participation of either sport is non-exclusive, that is, just because people took track and field does not necessarily mean they did not take swimming as well. As such, those 51 who took swimming could have all potentially done track and field, which means all 51 students.

Example Question #1 : How To Add Integers

Of 300 students, 120 are enrolled in math club, 150 are enrolled in chess club, and 100 are enrolled in both. How many students are not members of either club?

Possible Answers:

Correct answer:

Explanation:

There are 120 students in the math club and 150 students in the chess club, for a total membership of 270. However, 100 students are in both clubs, which means they are counted twice. You simply subtract 100 from 270, which will give you a total of 170 different students participating in both clubs. This means that the remaining 130 students do not participate in either club.

Example Question #2 : How To Add Integers

Choose the answer which best solves the following equation:

Possible Answers:

Correct answer:

Explanation:

When adding integers, one needs to pay close attention to the sign.  When you add a negative integer, it's the same thing as subtracting that integer.  Therefore:

Example Question #3 : How To Add Integers

Choose the answer below which best solves the following equation:

Possible Answers:

Correct answer:

Explanation:

The sum of any two negative numbers will be negative.  Remember, also, that adding a negative number is like subtracting it.  Therefore: 

Example Question #121 : Integers

Apples are sold by whole bushels. You cannot purchase part of a bushel. There are 126 apples in a bushel.

Sam is a caterer who needs to bake 300 pies to sell at the county fair. If it takes 4 apples to make a pie, how many bushels must Sam order to ensure he has enough apples for his pies?

Possible Answers:

10

9

9.5

12

11

Correct answer:

10

Explanation:

Because Sam needs to make 300 pies, and each pie needs 4 apples, the number of apples he needs is

300 x 4 = 1200.

To determine how many bushels Sam needs, divide the total number of apples by the number of apples sold in a bushel.

1200 / 126 = 9.524

Because apples are sold by the whole bushel, Sam cannot order part of a bushel. In order to make sure he has sufficient apples, he will need to order 10 bushels.

Example Question #131 : Integers

Which of the following integers is divisible by ?

Possible Answers:

Correct answer:

Explanation:

In order to find a number divisible by 6, you must find a number divisible by both of its factors — 2 and 3. Only even numbers are divisible by 2, so 81 is eliminated. In order to be divisible by 3, the sum of the digits has to be divisible by 3.

The sum of the digits of 316 is  3 + 1 + 6 = 10.

For 240, the sum is 2 + 4 = 6.

For 118, the sum is 1 + 1 + 8 = 10.

Only 6 is divisible by 3.

Example Question #1 : How To Divide Integers

Which of the following rules makes the expression  an integer?

Possible Answers:

 is a multiple of

 divided by  has a remainder of

 divided by  has a remainder of

All of these rules make  an integer.

None of these rules makes  an integer.

Correct answer:

 divided by  has a remainder of

Explanation:

4 is already an integer, so we need to make sure x/10 is an integer too.  

Multiples of 5 won't work. For example, 5 is a multiple of 5 but 5/10 isn't an integer. Similarly, if x/10 leaves a remainder of 5, x/10 isn't an integer. For example, 15/10 leaves a remainder of 5 and isn't an integer.  

If x/10 has no remainder, then it must be an integer. For example, 10/10 and 20/10 both leave no remainders and simplify to the integers 1 and 2, respectively. 

Example Question #13 : Operations

The remainder of  is .

Quantity A:

Quantity B: 

Possible Answers:

Quantity A is larger.

The two quantities are equal.

The relationship between the two quantities cannot be determined.

Quantity B is larger.

Correct answer:

The relationship between the two quantities cannot be determined.

Explanation:

If the remainder of  is , we know that  could be:

Since this generates an entire list of values, we cannot know which quantity is larger.  

Do not be tricked by the question, which is trying to get you to say that they are equal!

Example Question #783 : Gre Quantitative Reasoning

The remainder of  is .

The remainder of  is .

Which of the following is a potential value for ?

Possible Answers:

Correct answer:

Explanation:

Begin by writing out a few possible values for  and .  

Since the remainder of  is , we can list:

Since the remainder of  is , we can list:

Since  (which is ) is your smallest possible value, you know that  and  are not options.  You cannot derive either  or  from the values given.  

Therefore, the only option that is left is , which is equal to .

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