ACT Math : Arithmetic

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #691 : Arithmetic

Define an operation  as follows:

For all real numbers ,

Evaluate: .

Possible Answers:

The expression is undefined.

None of the other responses is correct.

Correct answer:

Explanation:

, or, equivalently,

Example Question #3 : Absolute Value

Define .

Evaluate .

Possible Answers:

Correct answer:

Explanation:

, or, equivalently,

Example Question #1 : How To Find Absolute Value

Define an operation  as follows:

For all real numbers ,

Evaluate .

Possible Answers:

Correct answer:

Explanation:

Example Question #692 : Arithmetic

Define .

Evaluate .

Possible Answers:

Correct answer:

Explanation:

Example Question #693 : Arithmetic

Define an operation  as follows:

For all real numbers ,

Evaluate 

Possible Answers:

Both  and 

Correct answer:

Explanation:

Example Question #11 : How To Find Absolute Value

What is the minimum value for  if ?

Possible Answers:

Correct answer:

Explanation:

When solving an absolute value equation, you should remember that you can have either a positive or a negative value in the absolute value. So, for instance:

 means that  can be either  or .

Thus, for this question, you know that  can mean:

Then, you just solve each and get:

Thus,  is the minimum possible value for .

Example Question #694 : Arithmetic

Simplify .

Possible Answers:

Correct answer:

Explanation:

Begin by simplifying the contents of the absolute value:

Remember that the absolute value of a negative number is a positive value. Thus:

 

Example Question #697 : Arithmetic

What is the largest possible value for  if ?

Possible Answers:

Correct answer:

Explanation:

When solving an absolute value equation, you should remember that you can have either a positive or a negative value in the absolute value. So, for instance:

 means that  can be either  or .

Thus, for this question, you know that . Start by dividing by  on both sides. This will give you:

Now, from this, we know:

Solve each equation for . The first is:

The second is . You can tell that this is going to end up being negative. You do not even need to finish. The larger value will be the positive one, .

Example Question #13 : How To Find Absolute Value

Evaluate the following expression: 

Possible Answers:

Correct answer:

Explanation:

First use order of operations (PEMDAS which stands for Parentheses, Exponents, Multiplication, Division, Addition, and Subraction) to evaluate the inner part of the absolute value:

First multiply 

.

Then subtract that from .

.

Absolute value means the distance away from zero, and distance is always positive.

Thus:  is the answer

Example Question #695 : Arithmetic

Evaluate the expression if  and .

Possible Answers:

Correct answer:

Explanation:

To solve, we replace each variable with the given value.

Simplify. Remember that terms inside of the absolute value are always positive.

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