ASVAB Math Tips: Solving for the n Factorial

As you study for the upcoming Armed Forces Aptitude Test or ASVAB, you may encounter questions asking you to complete up to n faculties written as exclamation points. In this article I will explain what this concept is and how to solve related problems by doing ASVAB math preparation.

Factorial is very similar to the word "factor" but don't confuse the two. When you are asked to find the factors in a certain equation, it means you want to know the division of the equation. For example, if you are given the number 36 and asked to find the factors, you must find all the numbers that can be multiplied to get the product of 36.

36 can be found by multiplying the following numbers:

1×36 2×18 3×12 4×9 6×6

However, faculty is a completely different concept. It is written as a number followed by an exclamation point and tells you to take a number and multiply it by a number less than that number.

For example, if you see a problem that is 5!

this is "5 factorial" and you fit this equation as follows:

5! = 5x4x3x2x1

The numbers are found by taking the first number and subtracting 1 to get the next value.

5 – 1 = 4, this is your second score

4 – 1 = 3, this is your third score

3 – 1 = 2, this is your fourth grade

2 – 1 = 1, that's your final score

If we factor 5, we get only 5 and 1. Since 5 is prime, only 5 x 1 = 5

When counting 5! we get 5 x 4 x 3 x 2 x 1 above, which is multiplied by 120

This is a relatively simple concept, but the tricky part is that many students or many examiners confuse this concept with the concept of multiplication of factors rather than multiplying by all the smaller numbers.

Let's look at one last example. When asked to factor and find the factor of 8, your appropriate answer would be as follows:

Factor of 8

1×8 2×4

8 faculties

8! = 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 40320