math help

What is 9/100 + 7/12?

What is 9/100 + 7/12?

This is how you add

9
100
+
7
12

Step 1

We can't add two fractions with different denominators (the bottom number). So you need to get a common denominator - both bottom numbers need to match. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator.

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

9/100 times 12

Do the same for the second term. We multiply 7 by 100, and get 700, then multiply 100 by 12 and get 1200.

7/12 times 100

So now our fractions look like this:

108
1200
+
700
1200

Step 2

Since our denominators match, we can add the numerators.

108 + 700 = 808

So the answer is:

808
1200

Step 3

Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction?

To find out, we try dividing it by 2...

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

808
1200
÷ 2 =
404
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:

404
600
÷ 2 =
202
300

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:

202
300
÷ 2 =
101
150

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. 103 is larger than 101. So we're done reducing.

And we're done! Here's the final answer to 9/100 + 7/12

9
100
+
7
12
=
101
150
© 2014 Randy Tayler