math help

What is 21/63 + 1/6?

What is 21/63 + 1/6?

Here's how to add

21
63
+
1
6

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 6, and get 126, then we multiply 63 by 6 and get 378.

21/63 times 6

Now for the second term. You multiply 1 by 63, and get 63, then multiply 63 by 6 and get 378.

1/6 times 63

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

126
378
+
63
378

Step 2

Since our denominators match, we can add the numerators.

126 + 63 = 189

Answer:

189
378

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:

189
378
÷ 3 =
63
126

Now, try the same number again.

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

63
126
÷ 3 =
21
42

Now, try the same number again.

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

21
42
÷ 3 =
7
14

Now, try the same number again.

Nope. Try the next prime number, 5...

Nope. Try the next prime number, 7...

Are both the numerator and the denominator evenly divisible by 7? Yes! So we reduce it:

7
14
÷ 7 =
1
2

Now, try the same number again.

No good. 7 is larger than 1. So we're done reducing.

Congratulations! Here's your final answer to 21/63 + 1/6

21
63
+
1
6
=
1
2
© 2014 Randy Tayler