math help

What is 30/50 + 2/7?

What is 30/50 + 2/7?

Here's how you add

30
50
+
2
7

Step 1

We still have different denominators (bottom numbers), though, so we need to get a common denominator. This will make the bottom numbers match. Multiply the denominators together first. Now, multiply each numerator by the other term's denominator.

Now we multiply 30 by 7, and get 210, then we multiply 50 by 7 and get 350.

30/50 times 7

Now for the second term. You multiply 2 by 50, and get 100, then multiply 50 by 7 and get 350.

2/7 times 50

This gives us a new problem that looks like so:

210
350
+
100
350

Step 2

Since our denominators match, we can add the numerators.

210 + 100 = 310

That gives us an answer of

310
350

Step 3

Can this fraction be reduced?

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

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

310
350
÷ 2 =
155
175

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:

155
175
÷ 5 =
31
35

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. 37 is larger than 31. So we're done reducing.

And we're done! Here's the final answer to 30/50 + 2/7

30
50
+
2
7
=
31
35
© 2014 Randy Tayler