Pre-Algebra : Number Theory

Study concepts, example questions & explanations for Pre-Algebra

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Example Questions

Example Question #41 :Number Theory

你得到when you multiply an even number with an odd number?

Possible Answers:

Irrational number

Prime number

Odd number

Imaginary number

Even number

Correct answer:

Even number

Explanation:

For example, take an even number likeand an odd number like. Their product iswhich 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?

I.rational

II.irrational

III.integer

IV.imaginary

V.composite

Possible Answers:

IIonly

I, III, V

IIIandVonly

II, IV

IandIIIonly

Correct answer:

I, III, V

Explanation:

Even though it's a radical, we can simplify.

Check the answer.

The answer is.

is an integer and a composite number with factors of. Furthermore, it can be expressed a rational number.

Thus, the final answer isI, III, V.

Example Question #43 :Number Theory

Which is a square number?

Possible Answers:

Correct answer:

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. We can multiplytwice to get the perfect square.

Example Question #44 :Number Theory

What are odd numbers?

Possible Answers:

All the digits of the integer must have,,,, or

Integers that have a ones digit that ends in,,,, or

Integers that have a ones digit that ends in,,,, or

Integers that have a ones digit that ends in,,,, or

Integers that have a ones digit that ends in,,,, or

Correct answer:

Integers that have a ones digit that ends in,,,, or

Explanation:

In order to determine if a number is odd, we will check the ones digit. It must contain,,,, or. The answer is integers that have a ones digit that ends in,,,, or.

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:

Correct answer:

Explanation:

Whole numbers start fromand include all positive integers. On the other hand, natural numbers are all positive integers that we can count starting from. The only difference is thatis found in whole numbers but not in the natural numbers series. Thus,is the correct answer.

Example Question #46 :Number Theory

Which of the following is an odd number?

I.

II.

III.

IV.

V.

Possible Answers:

I, III, V

I, III, IV

II, V

II, III, V

II, III, IV

Correct answer:

II, III, V

Explanation:

Odd numbers are integers that have a ones digit that ends in,,,, or. ChoicesII, III, Vare odd numbers because they have a ones digit of,, andrespectively.

# 47例问题:Number Theory

What is the product of two nonidentical prime numbers?

Possible Answers:

Composite number

Cubic number

Zero

Prime number

Square 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 #48 :Number Theory

你得到when you divide two negative integers?

Possible Answers:

Irrational number

理性的numbers

Integers

Zero

One

Correct answer:

理性的numbers

Explanation:

For example, we can take the negative integersand. When we divide, we get an answer of. This is an integer and a rational number. However, if we reverse it, we get an answer of. 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:

Which numbers in the set arewhole numbers?

Possible Answers:

Correct answer:

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 areand, which are neither negative nor have decimals.

Example Question #50 :Number Theory

can correctly be considered all of the following types of number, EXCEPT:

Possible Answers:

Negative

Integer

Natural

理性的

Real

Correct answer:

Natural

Explanation:

Negative numbers are integers, they are real, and they are rational. Natural numbers, by definition, are whole and non-negative numbers. Therefore,is NOT a natural number.

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