math help

What is 21/11 + 10/12?

What is 21/11 + 10/12?

Here's how you add

21
11
 +
10
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 10 by 11, and get 110, then multiply 11 by 12 and get 132.

10/12 times 11

The problem now has new fractions to add:

252
132
 +
110
132

Step 2

Since our denominators match, we can add the numerators.

252 + 110 = 362

The sum we get is

362
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:

362
132
 ÷ 2 =
181
66

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 3...

Nope! So now we try the next greatest prime number, 5...

Nope! So now we try the next greatest prime number, 7...

Nope! So now we try the next greatest prime number, 11...

Nope! So now we try the next greatest prime number, 13...

Nope! So now we try the next greatest prime number, 17...

Nope! So now we try the next greatest prime number, 19...

Nope! So now we try the next greatest prime number, 23...

Nope! So now we try the next greatest prime number, 29...

Nope! So now we try the next greatest prime number, 31...

Nope! So now we try the next greatest prime number, 37...

Nope! So now we try the next greatest prime number, 41...

Nope! So now we try the next greatest prime number, 43...

Nope! So now we try the next greatest prime number, 47...

Nope! So now we try the next greatest prime number, 53...

Nope! So now we try the next greatest prime number, 59...

Nope! So now we try the next greatest prime number, 61...

Nope! So now we try the next greatest prime number, 67...

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

There you have it! Here's the final answer to 21/11 + 10/12

21
11
 +
10
12
 =
181
66
© 2014 Randy Tayler

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