Question

What is 78/21 as a reduced fraction?

Answer 1

I do it like this: do they have any common divisors? 3 seems to be one. Let's divide both by 3:

78/3=26
21/3=7

so we can already reduce it to  26/7.
Do we like it? Well, we could reduce more, could we?
No, we can't. 7 is a product of 1 and 7, and no other natural numbers, so the only way to reduce it would be if 26 was divisible by 7, which it isn't.

So the reduced fraction is 26/7.

This is an improper fraction, and we can make it proper: how many times does 7 fit into 26? 3 (that's 21). And 5 is left.

So the final answer is 3 and  5/7.

Answer 2

First, we find the GCF of 78 and 21. The GCF of 78 and 21 is 3, so we divide by 3. $\frac{78:3}{21:3}=\boxed{\boxed{ \frac{26}{7}}}$