math help

What is 21/11 + 4/10?

What is 21/11 + 4/10?

Here's how we add

21
11
+
4
10

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 10, and get 210, then we multiply 11 by 10 and get 110.

21/11 times 10

Do the same for the second term. We multiply 4 by 11, and get 44, then multiply 11 by 10 and get 110.

4/10 times 11

The problem now has new fractions to add:

210
110
+
44
110

Step 2

Since our denominators match, we can add the numerators.

210 + 44 = 254

The sum we get is

254
110

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:

254
110
÷ 2 =
127
55

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...

No good. 59 is larger than 55. So we're done reducing.

Congratulations! Here's your final answer to 21/11 + 4/10

21
11
+
4
10
=
127
55
© 2014 Randy Tayler