math help

What is 9/34 + 3/12?

What is 9/34 + 3/12?

This is how you add

9
34
+
3
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 34 by 12 and get 408.

9/34 times 12

Do the same for the second term. We multiply 3 by 34, and get 102, then multiply 34 by 12 and get 408.

3/12 times 34

The problem now has new fractions to add:

108
408
+
102
408

Step 2

Since our denominators match, we can add the numerators.

108 + 102 = 210

This yields the answer

210
408

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:

210
408
÷ 2 =
105
204

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:

105
204
÷ 3 =
35
68

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...

Nope. Try the next prime number, 29...

Nope. Try the next prime number, 31...

Nope. Try the next prime number, 37...

No good. 37 is larger than 35. So we're done reducing.

Congratulations! Here's your final answer to 9/34 + 3/12

9
34
+
3
12
=
35
68
© 2014 Randy Tayler