Pre-Algebra : Integers and Types of Numbers

Study concepts, example questions & explanations for Pre-Algebra

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Example Questions

Example Question #31 : Integers And Types Of Numbers

What is a composite number?

Possible Answers:

Negative integers

A positive integer with at least one other factor besides one and itself

Cubic numbers

A positive integer with just factors of one and itself

Irrational numbers

Correct answer:

A positive integer with at least one other factor besides one and itself

Explanation:

Composite numbers have at least one factor other than one and itself. For example, \(\displaystyle 10\) is a composite number. The factors are \(\displaystyle 1, 2, 5, 10\)

Example Question #32 : Integers And Types Of Numbers

What do you get when you multiply an even number with an odd number?

Possible Answers:

Prime number

Odd number

Even number

Irrational number

Imaginary number

Correct answer:

Even number

Explanation:

For example, take an even number like \(\displaystyle 2\) and an odd number like \(\displaystyle 5\). Their product is \(\displaystyle 10\) which is an even number. No matter what examples we use; we will find that the answer is always even. Furthermore, it can never be a square number because the multiplicand and multiplier will be two different numbers (one odd and one even).

Example Question #42 : Number Theory

What kind of number is \(\displaystyle \sqrt{16}\)?

I. rational

II. irrational

III. integer

IV. imaginary

V. composite

Possible Answers:

II only

II, IV

III and V only

and III only

I, III, V

Correct answer:

I, III, V

Explanation:

Even though it's a radical, we can simplify\(\displaystyle \sqrt{16}\).

\(\displaystyle \sqrt{16}=4\)

Check the answer.

\(\displaystyle 4*4=16\)

The answer is \(\displaystyle 4\)

\(\displaystyle 4\) is an integer and a composite number with factors of \(\displaystyle 1, 2, 4\). Furthermore, it can be expressed a rational number \(\displaystyle (4=\frac{4}{1})\).

Thus, the final answer is I, III, V.

Example Question #33 : Integers And Types Of Numbers

Which is a square number?

Possible Answers:

\(\displaystyle 35\)

\(\displaystyle 1234\)

\(\displaystyle 121\)

\(\displaystyle 89\)

\(\displaystyle 99\)

Correct answer:

\(\displaystyle 121\)

Explanation:

Square numbers have one factor. If that factor is multiplied by itself, then the number becomes a perfect square. The only number in the selection that meets this requirement is \(\displaystyle 121\). We can multiply \(\displaystyle 11\) twice to get the perfect square \(\displaystyle 121\)

Example Question #44 : Number Theory

What are odd numbers?

Possible Answers:

All the digits of the integer must have \(\displaystyle 1\)\(\displaystyle 3\)\(\displaystyle 5\)\(\displaystyle 7\), or \(\displaystyle 9\)  

Integers that have a ones digit that ends in \(\displaystyle 1\)\(\displaystyle 2\)\(\displaystyle 5\)\(\displaystyle 8\), or \(\displaystyle 9\) 

Integers that have a ones digit that ends in \(\displaystyle 0\)\(\displaystyle 2\)\(\displaystyle 4\)\(\displaystyle 6\), or \(\displaystyle 8\) 

Integers that have a ones digit that ends in \(\displaystyle 1\)\(\displaystyle 5\)\(\displaystyle 6\)\(\displaystyle 8\), or \(\displaystyle 9\) 

Integers that have a ones digit that ends in \(\displaystyle 1\)\(\displaystyle 3\)\(\displaystyle 5\)\(\displaystyle 7\), or \(\displaystyle 9\)

Correct answer:

Integers that have a ones digit that ends in \(\displaystyle 1\)\(\displaystyle 3\)\(\displaystyle 5\)\(\displaystyle 7\), or \(\displaystyle 9\)

Explanation:

In order to determine if a number is odd, we will check the ones digit. It must contain \(\displaystyle 1\)\(\displaystyle 3\)\(\displaystyle 5\)\(\displaystyle 7\), or \(\displaystyle 9\). The answer is integers that have a ones digit that ends in \(\displaystyle 1\)\(\displaystyle 3\)\(\displaystyle 5\)\(\displaystyle 7\), or \(\displaystyle 9\)

Example Question #45 : Number Theory

What number is found in the set of whole numbers but not in the set of natural numbers?

Possible Answers:

\(\displaystyle -1\)

\(\displaystyle 1\)

\(\displaystyle \frac{1}{2}\)

\(\displaystyle 0\)

\(\displaystyle \pi\)

Correct answer:

\(\displaystyle 0\)

Explanation:

Whole numbers start from \(\displaystyle 0\) and include all positive integers. On the other hand, natural numbers are all positive integers that we can count starting from \(\displaystyle 1\). The only difference is that \(\displaystyle 0\) is found in whole numbers but not in the natural numbers series. Thus, \(\displaystyle 0\) is the correct answer. 

Example Question #46 : Number Theory

Which of the following is an odd number?

I. \(\displaystyle 12\)

II. \(\displaystyle 33\)

III. \(\displaystyle 71\)

IV. \(\displaystyle 54\)

V. \(\displaystyle 89\)

Possible Answers:

II, III, V

II, V

II, III, IV

I, III, V

I, III, IV

Correct answer:

II, III, V

Explanation:

Odd numbers are integers that have a ones digit that ends in \(\displaystyle 1\)\(\displaystyle 3\)\(\displaystyle 5\)\(\displaystyle 7\), or \(\displaystyle 9\). Choices II, III, V  are odd numbers because they have a ones digit of \(\displaystyle 3\)\(\displaystyle 1\), and \(\displaystyle 9\) respectively. 

Example Question #34 : Integers And Types Of Numbers

What is the product of two nonidentical prime numbers?

Possible Answers:

Square number

Composite number

Prime number

Zero

Cubic number

Correct answer:

Composite number

Explanation:

When you take two prime numbers, you are creating a composite number. A compositie number has at least one more factor than one and itself. Since you multiply two prime numbers, you are increasing the factors of the new number. 

Example Question #35 : Integers And Types Of Numbers

What do you get when you divide two negative integers?

Possible Answers:

Rational numbers

Integers

One

Irrational number

Zero

Correct answer:

Rational numbers

Explanation:

For example, we can take the negative integers \(\displaystyle -10\) and \(\displaystyle -5\). When we divide \(\displaystyle \frac{-10}{-5}\), we get an answer of \(\displaystyle 2\). This is an integer and a rational number. However, if we reverse it \(\displaystyle \frac{-5}{-10}\), we get an answer of \(\displaystyle \frac{1}{2}\). This is not an integer but it is a rational number. Integers can be rational numbers as they are expressed as any number over one. Futhermore, rational numbers are defined as the expression of any quotient or fraction possessing a non-zero denominator. Thus, our answer is rational numbers. 

Example Question #49 : Number Theory

Given the following set of numbers:

\(\displaystyle -4, -2, -0.5, 2, 15, 20.25\)

Which numbers in the set are whole numbers?

Possible Answers:

\(\displaystyle 2, 15, 20.25\)

\(\displaystyle 2, 15\)

\(\displaystyle -0.5, 20,25\)

\(\displaystyle -4, -2, 2, 15\)

\(\displaystyle 2\)

Correct answer:

\(\displaystyle 2, 15\)

Explanation:

A whole number is any number without a fraction or decimal, but negative numbers are NOT whole numbers. Therefore, the only correct choices from this set are \(\displaystyle 2\) and \(\displaystyle 15\), which are neither negative nor have decimals. 

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