SAT Math : Negative Numbers

Study concepts, example questions & explanations for SAT Math

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Example Questions

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Example Question #1 : How To Multiply Negative Numbers

Solve the following equation:

Possible Answers:

Correct answer:

Explanation:

If there are two negative signs, then the answer will be positive. If there were only one negative sign, the answer will be negative. 

Example Question #41 : Integers

Simplify the following expression:

Possible Answers:

Correct answer:

Explanation:

Simplify the following expression:

Let's begin by expanding the inside of the parentheses.

Now, it is important to use all three negative signs. The first two will cancel out, but the third one will remain, ensuring our final answer will be negative.

Example Question #1 : How To Divide Negative Numbers

What is ?

Possible Answers:

45

Correct answer:

Explanation:

A negative number divided by a negative number always results in a positive number.  divided by  equals . Since the answer is positive, the answer cannot be  or any other negative number.

Example Question #1 : How To Divide Negative Numbers

Solve for :

Possible Answers:

Correct answer:

Explanation:

Begin by isolating your variable.

Subtract  from both sides:

, or 

Next, subtract  from both sides:

, or 

Then, divide both sides by :

Recall that division of a negative by a negative gives you a positive, therefore:

 or 

Example Question #42 : Integers

Divide:  

Possible Answers:

Correct answer:

Explanation:

Anytime a positive number is divided by a negative number, or vice versa, the end result is a negative number.  Find the common factors.

Example Question #2 : How To Divide Negative Numbers

Divide:  

Possible Answers:

Correct answer:

Explanation:

In order to divide, it is necessary to simplify the numerator and denominator first.

Divide both negative numbers.  Two negatives divided will result in a positive number.

The answer is .

Example Question #1 : How To Add Negative Numbers

Add:  

Possible Answers:

Correct answer:

Explanation:

Anytime a negative number is added, it is similar to subtraction.  Recovert the expression to the correct form.  Simplify.

The correct answer is .

Example Question #2 : How To Add Negative Numbers

Add the negative numbers:  

Possible Answers:

Correct answer:

Explanation:

In order to add the negative numbers, we need to eliminate the double signs and the parentheses.  A positive and a negative sign will result in a negative sign.

Evaluate the terms on the right.

The answer is:  

Example Question #1 : Negative Numbers

a, b, c are integers.

abc < 0

ab > 0

bc > 0

Which of the following must be true?

Possible Answers:

a + b < 0

a > 0

ac < 0

b > 0

a – b > 0

Correct answer:

a + b < 0

Explanation:

Let's reductively consider what this data tells us.

Consider each group (a,b,c) as a group of signs.

From abc < 0, we know that the following are possible:

(–, +, +), (+, –, +), (+, +, –), (–, –, –)

From ab > 0, we know that we must eliminate (–, +, +) and (+, –, +)

From bc > 0, we know that we must eliminate (+, +, –)

Therefore, any of our answers must hold for (–, –, –)

This eliminates immediately a > 0, b > 0

Likewise, it eliminates a – b > 0 because we do not know the relative sizes of a and b. This could therefore be positive or negative.

Finally, ac is a product of negatives and is therefore positive. Hence ac < 0 does not hold.

We are left with a + b < 0, which is true, for two negatives added must be negative.

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