math help

What is 30/50 + 7/8?

What is 30/50 + 7/8?

Here's how we add

30
50
+
7
8

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 30 by 8, and get 240, then we multiply 50 by 8 and get 400.

30/50 times 8

Now for the second term. You multiply 7 by 50, and get 350, then multiply 50 by 8 and get 400.

7/8 times 50

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

240
400
+
350
400

Step 2

Since our denominators match, we can add the numerators.

240 + 350 = 590

That gives us the sum, which is

590
400

Step 3

Now, do we need to simplify this fraction?

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

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

590
400
÷ 2 =
295
200

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 3...

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

Are both the numerator and the denominator evenly divisible by 5? Yes! So we reduce it:

295
200
÷ 5 =
59
40

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 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. So next you try the next prime number, which is 31...

No good. So next you try the next prime number, which is 37...

No good. So next you try the next prime number, which is 41...

No good. 41 is larger than 40. So we're done reducing.

And we're done! Here's the final answer to 30/50 + 7/8

30
50
+
7
8
=
59
40
© 2014 Randy Tayler