math help

What is 78/92 + 5/10?

What is 78/92 + 5/10?

This is how we add

78
92
+
5
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 78 by 10, and get 780, then we multiply 92 by 10 and get 920.

78/92 times 10

Now for the second term. You multiply 5 by 92, and get 460, then multiply 92 by 10 and get 920.

5/10 times 92

This gives us a new problem that looks like so:

780
920
+
460
920

Step 2

Since our denominators match, we can add the numerators.

780 + 460 = 1240

That gives us an answer of

1240
920

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:

1240
920
÷ 2 =
620
460

So far so good... let's try to divide by that number again.

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

620
460
÷ 2 =
310
230

So far so good... let's try to divide by that number again.

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

310
230
÷ 2 =
155
115

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
115
÷ 5 =
31
23

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. 29 is larger than 23. So we're done reducing.

And we're done! Here's the final answer to 78/92 + 5/10

78
92
+
5
10
=
31
23
© 2014 Randy Tayler