math help

What is 30/50 + 3/12?

What is 30/50 + 3/12?

Here's how we add

30
50
+
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 30 by 12, and get 360, then we multiply 50 by 12 and get 600.

30/50 times 12

Now for the second term. You multiply 3 by 50, and get 150, then multiply 50 by 12 and get 600.

3/12 times 50

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

360
600
+
150
600

Step 2

Since our denominators match, we can add the numerators.

360 + 150 = 510

That gives us the sum, which is

510
600

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:

510
600
÷ 2 =
255
300

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...

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

255
300
÷ 3 =
85
100

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...

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

85
100
÷ 5 =
17
20

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. 19 is larger than 17. So we're done reducing.

And we're done! Here's the final answer to 30/50 + 3/12

30
50
+
3
12
=
17
20
© 2014 Randy Tayler