Greatest Common Divisor (GCD) of 15 and 18
In this article we will calculate and work out the Greatest Common Divisor (GCD) of the numbers 15 and 18.
The GCD of 15 and 18 is the largest positive integer (a whole number with no decimal) that can be divided evenly into all of the numbers in the set.
You might have seen this called the Greatest Common Factor (GCF) or the Highest Common Factor (HCF). They all mean the same thing.
If you are calculating the Greatest Common Divisor of 15 and 18 yourself, the easiest way to do that might be to actually list out all of the divisors for each number and then find out what the greatest common divisor is.
For 15 and 18 those divisors look like this:
- Divisors for 15: 1, 3, 5, and 15
- Divisors for 18: 1, 2, 3, 6, 9, and 18
As you can see when you list out the divisors of each number, 3 is the greatest number that 15 and 18 divides into.
When working with larger numbers, though, listing through all of the divisors will take a lot of computer processing power.
When working with larger numbers, or even with smaller numbers when you want to find the Greatest Common Divisor of 15 and 18 in the most efficient way possible, we would use Prime Factors.
A Prime Number is one that is divisible only by itself and the number 1. And so a Prime Factor is a Prime Number which is also a Factor of 15 and 18.
The algorithm I use for this is much more efficient because there are far less Prime Factors in 15 and 18.
For 15 and 18 the Prime Factors are:
- Prime Factors for 15: 3 and 5
- Prime Factors for 18: 2 and 3
You can see again from the bolded number 3 that the Greatest Common Divisor of 15 and 18 is 3.
GCD(15,18) = 3
Hopefully I have been able to explain the GCD of 15 and 18 and given you some information that you can use to try this for yourself and calculate the Greatest Common Divisor of a new set of numbers.
Link To or Reference This Page
If you found this content useful in your research, please do us a great favor and use the tool below to make sure you properly reference us wherever you use it. We really appreciate your support!
"Greatest Common Divisor (GCD) of 15 and 18". DivisibleBot.com. Accessed on September 22, 2021. https://divisiblebot.com/greatest-common-divisor/15-18/.
"Greatest Common Divisor (GCD) of 15 and 18". DivisibleBot.com, https://divisiblebot.com/greatest-common-divisor/15-18/. Accessed 22 September, 2021.
Greatest Common Divisor (GCD) of 15 and 18. DivisibleBot.com. Retrieved from https://divisiblebot.com/greatest-common-divisor/15-18/.
Calculate Another Problem
Here are some sample calculations for you:
Here are some more random calculations for you: