Natural numbers are the numbers you use every day.

These numbers include values from one all the way up to infinity.

The numbers you can count with your fingers and toes are all natural numbers.

Natural Number Examples: 1, 2, 5, 18, 150, 1,586, 258,569.

Whole Numbers

Whole numbers are just like natural numbers except that they also include 0.

Integers

Did you notice how those number lines all started at 0? Number lines with integers can have every positive and negative number.

Rational Numbers

Another term for a fraction is a rational number. The word rational comes from the word ratio. In the case of rational numbers, it is a ratio of two integers.

Prime and Composite Numbers

You may have heard of prime numbers. Prime numbers are special because they can only be divided evenly by 1 and themselves. A number like six can be divided by 1, 6, 2, and 3. There will be no remainder when you divide by those numbers. A prime number like 7 can only be divided by 1 and 7 without a remainder.

• Can a negative number be a prime number? No. Negative numbers are not natural numbers. That means no fractions either.

• Can zero be a prime number? No. You need two divisors to make a prime. While zero can be divided by any number, you cannot divide by zero.

• Is one a prime number? No. You need two divisors to make a prime (one and itself). Technically, one only has one divisor and is not a prime number.

Composite number

The opposite of a prime number is a composite number. We talked about how six can be divided by 1, 6, 2, and 3. Six is a composite number because it is divisible by many different numbers and has no remainder.

Next Lesson: Integers, Decimals, and Fractions