High School Math : Factorials

Study concepts, example questions & explanations for High School Math

varsity tutors app store varsity tutors android store

Example Questions

Example Question #1 : Factorials

What is the value of  ? 

Possible Answers:

24

12

6

4

10

Correct answer:

24

Explanation:

! is the symbol for factorial, which means the product of the whole numbers less than the given number. 

Thus,

Example Question #1 : Factorials

What is the value of  ? 

Possible Answers:

Correct answer:

Explanation:

By definition, 

Example Question #1 : Factorials

Find the value of:

Possible Answers:

Correct answer:

Explanation:

The factorial sign (!) just tells us to multiply that number by every integer that leads up to it.  So,  can also be written as: 

To make this easier for ourselves, we can cancel out the numbers that appear on both the top and bottom:

Example Question #1 : Multiplying And Dividing Factorials

Solve the following expression.

Possible Answers:

Correct answer:

Explanation:

This expression can be simplified because all terms in the expression for 8! are also found in the expression for 10!. By writing the expression below, we are able to cancel 8!.

Example Question #2 : Multiplying And Dividing Factorials

Solve: 

Possible Answers:

Correct answer:

Explanation:

Both the numerator and denominator are factorials. If you expanded both, everything would cancel out except for  in the numerator. Multiply those together to get 720. 

Example Question #1 : Multiplying And Dividing Factorials

Simplify .

Possible Answers:

Correct answer:

Explanation:

Thus,   since the remaining terms cancel out. 56 is the simplified result. 

Example Question #1 : Factorials

Stewie has   marbles in a bag. How many marbles does Stewie have? 

Possible Answers:

Correct answer:

Explanation:

Simplifying this equation we notice that the 3's, 2's, and 1's cancel so

Alternative Solution

Example Question #1 : Multiplying And Dividing Factorials

Which of the following is NOT the same as ?

Possible Answers:

Correct answer:

Explanation:

The  cancels out all of  except for the parts higher than 4, this leaves a 6 and a 5 left to multilpy 

Example Question #4 : Multiplying And Dividing Factorials

Simplify and solve .

Possible Answers:

Correct answer:

Explanation:

Remember a number followed by a ! is a factorial. A factorial is the product of the given number and all of the numbers smaller than it down to zero. For example, .

Rather than do all of the math involved for , notice that  is the same as 

From here, the 's cancel out, leaving us with

Example Question #2 : Multiplying And Dividing Factorials

Which of the following is equivalent to ?

Possible Answers:

None of the other answers are correct.

Correct answer:

Explanation:

This is a factorial question. The formula for factorials is .

 

Learning Tools by Varsity Tutors