math help

What is 21/11 + 2/12?

What is 21/11 + 2/12?

Here's how we add

21
11
+
2
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 21 by 12, and get 252, then we multiply 11 by 12 and get 132.

21/11 times 12

Do the same for the second term. We multiply 2 by 11, and get 22, then multiply 11 by 12 and get 132.

2/12 times 11

The problem now has new fractions to add:

252
132
+
22
132

Step 2

Since our denominators match, we can add the numerators.

252 + 22 = 274

The sum we get is

274
132

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:

274
132
÷ 2 =
137
66

Now, try the same number again.

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

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...

Nope. Try the next prime number, 41...

Nope. Try the next prime number, 43...

Nope. Try the next prime number, 47...

Nope. Try the next prime number, 53...

Nope. Try the next prime number, 59...

Nope. Try the next prime number, 61...

Nope. Try the next prime number, 67...

No good. 67 is larger than 66. So we're done reducing.

Congratulations! Here's your final answer to 21/11 + 2/12

21
11
+
2
12
=
137
66
© 2014 Randy Tayler