math help

What is 21/33 + 4/9?

What is 21/33 + 4/9?

Here's how we add

21
33
+
4
9

Step 1

Can you add yet? Nope! The denominators don't match. We need a common denominator. So next we take both denominators and multiply them. Next, take each numerator and multiply it by the denominator of the other term.

So, we multiply 21 by 9, and get 189, then we multiply 33 by 9 and get 297.

21/33 times 9

Now for the second term. You multiply 4 by 33, and get 132, then multiply 33 by 9 and get 297.

4/9 times 33

We now have a new problem, that looks like this:

189
297
+
132
297

Step 2

Since our denominators match, we can add the numerators.

189 + 132 = 321

Answer:

321
297

Step 3

Now, do we need to simplify this fraction?

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

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

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

321
297
÷ 3 =
107
99

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...

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...

No good. 101 is larger than 99. So we're done reducing.

Congratulations! Here's your final answer to 21/33 + 4/9

21
33
+
4
9
=
107
99
© 2014 Randy Tayler