math help

What is 57/7 + 3/12?

What is 57/7 + 3/12?

This is how you add

57
7
+
3
12

Step 1

Can you add yet? Nope! The denominators don't match. We need a common denominator. So next we take both denominators and multiply them. Next, take each numerator and multiply it by the denominator of the other term.

So, we multiply 57 by 12, and get 684, then we multiply 7 by 12 and get 84.

57/7 times 12

Now for the second term. You multiply 3 by 7, and get 21, then multiply 7 by 12 and get 84.

3/12 times 7

We now have a new problem, that looks like this:

684
84
+
21
84

Step 2

Since our denominators match, we can add the numerators.

684 + 21 = 705

That gives us the sum, which is

705
84

Step 3

Now, do we need to simplify this fraction?

First, we attempt to divide it by 2...

Nope. Try the next prime number, 3...

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

705
84
÷ 3 =
235
28

Now, try the same number again.

Nope. Try the next prime number, 5...

Nope. Try the next prime number, 7...

Nope. Try the next prime number, 11...

Nope. Try the next prime number, 13...

Nope. Try the next prime number, 17...

Nope. Try the next prime number, 19...

Nope. Try the next prime number, 23...

Nope. Try the next prime number, 29...

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

Congratulations! Here's your final answer to 57/7 + 3/12

57
7
+
3
12
=
235
28
© 2014 Randy Tayler