math help

What is 9/100 + 9/12?

What is 9/100 + 9/12?

Here's how we add

9
100
+
9
12

Step 1

Of course, you can't add two fractions if the denominators (bottom numbers) don't match. To get a common denominator, multiply the denominators together. Then we fix the numerators by multiplying each one by their other term's denominator.

Now you 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 9 by 100, and get 900, then multiply 100 by 12 and get 1200.

9/12 times 100

The problem now has new fractions to add:

108
1200
+
900
1200

Step 2

Since our denominators match, we can add the numerators.

108 + 900 = 1008

This yields the answer

1008
1200

Step 3

The last step is to reduce the fraction if we can.

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:

1008
1200
÷ 2 =
504
600

Now, try the same number again.

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

504
600
÷ 2 =
252
300

Now, try the same number again.

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

252
300
÷ 2 =
126
150

Now, try the same number again.

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

126
150
÷ 2 =
63
75

Now, try the same number again.

Nope. Try the next prime number, 3...

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

63
75
÷ 3 =
21
25

Now, try the same number again.

Nope. Try the next prime number, 5...

Nope. Try the next prime number, 7...

Nope. Try the next prime number, 11...

Nope. Try the next prime number, 13...

Nope. Try the next prime number, 17...

Nope. Try the next prime number, 19...

Nope. Try the next prime number, 23...

No good. 23 is larger than 21. So we're done reducing.

Congratulations! Here's your final answer to 9/100 + 9/12

9
100
+
9
12
=
21
25
© 2014 Randy Tayler