Pre-Algebra : Number Theory

Study concepts, example questions & explanations for Pre-Algebra

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Example Questions

Example Question #6 : The Number System

Which of the following numbers is considered to be an irrational number?

 

Possible Answers:

Correct answer:

Explanation:

An irrational number cannot be represented as the quotient of two integers.

Irrational numbers do not terminate and are not repeat numbers.

Looking at the possible answers,

 can be reduced to , therefore it is an integer.

 by definition is a quotient of two integers and thus it is not an irrational number.

 can be rewritten as  and by definition is a quotient of two integers and thus it is not an irrational number.

 is a terminated decimal and therefore can be written as a fraction. Thus it is not an irrational number.

 is the number for  and does not terminate, therefore it is irrational.

Example Question #13 : Irrational Numbers

Add the following:  

Possible Answers:

Correct answer:

Explanation:

To add the numerator, first multiply the denominator to find the least common denominator.

The common denominator is:  

Rewrite the fractions.

Example Question #11 : Irrational Numbers

Which of the following choices is irrational?

Possible Answers:

Correct answer:

Explanation:

The meaning of irrational states that numbers cannot be rewritten as a ratio of integers. Of the following that could be simplified, the only possible choice of irrational numbers is .

The answer is .

All other options are rational because they can be written as either a fraction of integers or just an integer.

 

Example Question #71 : Number Theory

Which of the following is an irrational number?

Possible Answers:

Correct answer:

Explanation:

A rational number can be put in the form , it can be a terminating decimal, or it can be a repeating decimal.  is a continual number, therefore it is an irrational number.

Example Question #72 : Number Theory

Which of the following is an irrational number?

Possible Answers:

Correct answer:

Explanation:

An irrational number is any number that cannot be expressed as a ratio of integers.

Therefore,  is considered irrational because it cannot be expressed as a ratio of integers.

Example Question #73 : Number Theory

Which of the following is an irrational number?

Possible Answers:

Correct answer:

Explanation:

An irrational number is a number that cannot be expressed as a ratio of integers and cannot be expressed as terminating or repeating decimals.  

Therefore, the only answer that follows this definition is .

Example Question #74 : Number Theory

Which of the following is an irrational number?

Possible Answers:

Correct answer:

Explanation:

A rational number is any number that can be expressed as a fraction where both the numerator and denominator are integers. The denominator also cannot be equal to 0. In this set, the irrational number is  because the There is no fraction that can be made, it's decimal goes on and on and does not repeat in a pattern. Using the fraction test, we can prove that the following numbers are rational:

Example Question #1 : Number Lines

Which of the following numbers is depicted by the point on the number line?

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Possible Answers:

Correct answer:

Explanation:

The point lies halfway between  and , or at .

Example Question #1 : How To Plot Fractions On A Number Line

Plot the fraction  on the number line.

Possible Answers:

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Correct answer:

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Explanation:

The fraction  is less than  and greater than , so it must fall between those points on the number line. Negative numbers are to the left of  while positive numbers are to the right.

Because  is less than , the point must be closer to  than .

Example Question #2 : Number Theory

Find the distance between  and  on a number line.

Possible Answers:

Correct answer:

Explanation:

To find the distance on a number line:

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