math help

What is 100/72 + 3/10?

What is 100/72 + 3/10?

This is how we add

100
72
+
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 100 by 10, and get 1000, then we multiply 72 by 10 and get 720.

100/72 times 10

Now for the second term. You multiply 3 by 72, and get 216, then multiply 72 by 10 and get 720.

3/10 times 72

This gives us a new problem that looks like so:

1000
720
+
216
720

Step 2

Since our denominators match, we can add the numerators.

1000 + 216 = 1216

That gives us an answer of

1216
720

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:

1216
720
÷ 2 =
608
360

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:

608
360
÷ 2 =
304
180

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:

304
180
÷ 2 =
152
90

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:

152
90
÷ 2 =
76
45

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...

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. So next you try the next prime number, which is 43...

No good. So next you try the next prime number, which is 47...

No good. 47 is larger than 45. So we're done reducing.

And we're done! Here's the final answer to 100/72 + 3/10

100
72
+
3
10
=
76
45
© 2014 Randy Tayler