How to subtract negative numbers

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GRE Quantitative Reasoning › How to subtract negative numbers

Questions 1 - 3
1

Quantity A:

Quantity B:

Quantity A is greater

Quantity B is greater

The two quantities are equal

The relationship cannot be determined from the information given.

Explanation

Since both quantities have an , you can ignore this variable, which will give you and for quantities A and B, respectively. Since and are both negative numbers, must be bigger than , which means that no matter what numbers they are, Quantity A must be bigger.

2

Quantity A:

Quantity B:

Which of the following is true?

Quantity B is larger.

Quantity A is larger.

The two quantities are equal in size.

The relationship between the quantities cannot be determined.

Explanation

A problem like this one is very easy. All you need to do is manage your arithmetic well. Remember that when you subtract a negative number, this is the same as adding the positive of that number. Therefore, you can rewrite each of your quantities:

Quantity A:

Using a calculator, this comes out to be:

Quantity B:

Using a calculator, this comes out to be:

Therefore, quantity B is larger.

3

If and are integers such that and , what is the smallest possible value of ?

Explanation

To make as small as possible, let be as small as possible , and subtract the largest value of possible :

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