math help

What is 21/11 + 7/10?

What is 21/11 + 7/10?

Here's how to add

21
11
+
7
10

Step 1

We still have different denominators (bottom numbers), though, so we need to get a common denominator. This will make the bottom numbers match. Multiply the denominators together first. Now, multiply each numerator by the other term's denominator.

Now we multiply 21 by 10, and get 210, then we multiply 11 by 10 and get 110.

21/11 times 10

Now for the second term. You multiply 7 by 11, and get 77, then multiply 11 by 10 and get 110.

7/10 times 11

This gives us a new problem that looks like so:

210
110
+
77
110

Step 2

Since our denominators match, we can add the numerators.

210 + 77 = 287

That gives us an answer of

287
110

Step 3

Can this fraction be reduced?

First, we attempt to divide it by 2...

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...

Nope. Try the next prime number, 71...

Nope. Try the next prime number, 73...

Nope. Try the next prime number, 79...

Nope. Try the next prime number, 83...

Nope. Try the next prime number, 89...

Nope. Try the next prime number, 97...

Nope. Try the next prime number, 101...

Nope. Try the next prime number, 103...

Nope. Try the next prime number, 107...

Nope. Try the next prime number, 109...

Nope. Try the next prime number, 113...

No good. 113 is larger than 110. So we're done reducing.

Congratulations! Here's your final answer to 21/11 + 7/10

21
11
+
7
10
=
287
110
© 2014 Randy Tayler