math help

What is 72/63 + 1/4?

What is 72/63 + 1/4?

Here's how to add

72
63
+
1
4

Step 1

We can't add two fractions with different denominators (the bottom number). So you need to get a common denominator - both bottom numbers need to match. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator.

So we multiply 72 by 4, and get 288, then we multiply 63 by 4 and get 252.

72/63 times 4

Do the same for the second term. We multiply 1 by 63, and get 63, then multiply 63 by 4 and get 252.

1/4 times 63

So now our fractions look like this:

288
252
+
63
252

Step 2

Since our denominators match, we can add the numerators.

288 + 63 = 351

Now we have an answer.

351
252

Step 3

Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction?

To find out, we try dividing it by 2...

No good. So next you try the next prime number, which is 3...

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

351
252
÷ 3 =
117
84

So far so good... let's try to divide by that number again.

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

117
84
÷ 3 =
39
28

So far so good... let's try to divide by that number again.

No good. So next you try the next prime number, which is 5...

No good. So next you try the next prime number, which is 7...

No good. So next you try the next prime number, which is 11...

No good. So next you try the next prime number, which is 13...

No good. So next you try the next prime number, which is 17...

No good. So next you try the next prime number, which is 19...

No good. So next you try the next prime number, which is 23...

No good. So next you try the next prime number, which is 29...

No good. 29 is larger than 28. So we're done reducing.

And we're done! Here's the final answer to 72/63 + 1/4

72
63
+
1
4
=
39
28
© 2014 Randy Tayler