How do you reduce 28 over 35?

Answer 1

Start by factoring each number:

28 has factors of 2, 2, and 7

35 has factors of 5 and 7

28/35 can then drop the 7s since each has the same number of factors equal to 7. What remains are the dissimilar factors, thus revealing the lowest possible reduction:

2 * 2 = 4

5 = 5

Result is 4/5.

As a further example, let's take this a little further. Let's say that we are trying to reduce the fraction of 144/324. So, let's factor both the numerator and denominator:

144 has factors of 2, 2, 2, 2, 3, and 3

324 has factors of 2, 2, 3, 3, 3, and 3

Notice that both are easily made up of multiple twos and threes. I chose these numbers to keep things simple but to demonstrate the issue. So, both numbers have at least two twos and at least two threes, so eliminate the similar values: two 2s and two 3s from each. This results in only the following remaining:

From the original 144: only two 2s remain

From the original 324: only two 3s remain

Therefore, 144/324 reduced is (2 * 2) / (3 * 3) or 4/9.