math help

What is 9/100 + 4/12?

What is 9/100 + 4/12?

This is how to add

9
100
+
4
12

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 9 by 12, and get 108, then we multiply 100 by 12 and get 1200.

9/100 times 12

Now for the second term. You multiply 4 by 100, and get 400, then multiply 100 by 12 and get 1200.

4/12 times 100

This gives us a new problem that looks like so:

108
1200
+
400
1200

Step 2

Since our denominators match, we can add the numerators.

108 + 400 = 508

So what's the answer so far?

508
1200

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:

508
1200
÷ 2 =
254
600

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:

254
600
÷ 2 =
127
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...

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. So next you try the next prime number, which is 53...

No good. So next you try the next prime number, which is 59...

No good. So next you try the next prime number, which is 61...

No good. So next you try the next prime number, which is 67...

No good. So next you try the next prime number, which is 71...

No good. So next you try the next prime number, which is 73...

No good. So next you try the next prime number, which is 79...

No good. So next you try the next prime number, which is 83...

No good. So next you try the next prime number, which is 89...

No good. So next you try the next prime number, which is 97...

No good. So next you try the next prime number, which is 101...

No good. So next you try the next prime number, which is 103...

No good. So next you try the next prime number, which is 107...

No good. So next you try the next prime number, which is 109...

No good. So next you try the next prime number, which is 113...

No good. So next you try the next prime number, which is 127...

No good. So next you try the next prime number, which is 131...

No good. 131 is larger than 127. So we're done reducing.

And we're done! Here's the final answer to 9/100 + 4/12

9
100
+
4
12
=
127
300
© 2014 Randy Tayler