math help

What is 25/15 + 3/10?

What is 25/15 + 3/10?

Here's how we add

25
15
+
3
10

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 25 by 10, and get 250, then we multiply 15 by 10 and get 150.

25/15 times 10

Now for the second term. You multiply 3 by 15, and get 45, then multiply 15 by 10 and get 150.

3/10 times 15

This gives us a new problem that looks like so:

250
150
+
45
150

Step 2

Since our denominators match, we can add the numerators.

250 + 45 = 295

So what's the answer so far?

295
150

Step 3

Can this fraction be reduced?

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

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
150
÷ 5 =
59
30

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. 31 is larger than 30. So we're done reducing.

And we're done! Here's the final answer to 25/15 + 3/10

25
15
+
3
10
=
59
30
© 2014 Randy Tayler