Q:
# Is 19 a prime number?

**The number 19 is the eighth prime number.** A prime number is a positive, whole number that is only divisible by one and itself. Nineteen is also the seventh Mersenne prime exponent, which is a prime number that is one less than a power of two.

Out of the first 100 numbers, 25 of them are prime numbers. The opposite of a prime number is a composite number. Because all even numbers are divisible by two, the number two is the only even prime number. Similarly, no prime numbers that are higher than five end in five. One is a unique number because it is neither a prime number nor a composite number.

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Q:
## What is a number model?

A: A number model is a sentence that shows how a series of numbers are related. An example of a basic number model could be 12+3=15.... Full Answer >Filed Under: -
Q:
## Why does pi not have units?

A: Pi does not have units because it is a number, not a measurement. However, pi is sometimes treated like a unit when referring to angle measurements because... Full Answer >Filed Under: -
Q:
## What is a whole number?

A: A whole number belongs to the set of integers that are equal to or greater than zero. For example, the set of numbers {0, 1, 2, 3, 4, 5, ...} contains all ... Full Answer >Filed Under: -
Q:
## How do you find the magnitude of a complex number?

A: The magnitude, or modulus, of a complex number in the form z = a + bi is the positive square root of the sum of the squares of a and b. In other words, |z|... Full Answer >Filed Under: