+5 The biggest common factor, as it sounds, is the largest number, which evenly breaks into two or more larger numbers. For example, the greatest common factor (GCF) of 15 and 25 is 5 because 5 is the largest number that goes into 15 and 25 evenly. https://www.gcfcalculator.net/
To find the GCF of smaller numbers like 12 or 16, it may be easier to find all the factors list and find the greatest common factor. For large numbers like 490 and 819, however, you need a faster method.
The first step is to do a prime factorization of each number. Find any number (2 works) that evenly divides 490 and you get 245. . So 7 * 7 * 5 * 2 = 490. These four numbers circled in red are all prime and can no longer be considered, so you need to be done.
This is the prime factorization of 490. Now you can do the same with your other number, 819. , the prime factors of 819 are 3,3,7 and 13.
Now we should compare the prime factors of both numbers: 819 = 3 ∗ 3 ∗ 7 ∗ 13 490 = 2 ∗ 5 ∗ 7 ∗ 7 So what we want Let’s try another pair of numbers, 1012 and 10580.
The prime factorization of the numbers shows this situation: 1012 = 2 ∗ 2 ∗ 11 ∗ 23 105804aaaaaaaaaaaaaa * we will use two numbers ∗ 40aa4 ∗ 4023aaaaaaaa4 We can't use the other 23 because 1012 has only one, and we can't use 11 because 10580 doesn't have any numbers in common and multiply them to If you need more help, please read another lesson on our key common factors or use a search engine such as Google to find more information.
