math help

What is 20/64 + 1/7?

What is 20/64 + 1/7?

Let's add

20
64
+
1
7

Step 1

We can't add two fractions with different denominators (the bottom number). So you need to get a common denominator - both bottom numbers need to match. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator.

So we multiply 20 by 7, and get 140, then we multiply 64 by 7 and get 448.

20/64 times 7

Do the same for the second term. We multiply 1 by 64, and get 64, then multiply 64 by 7 and get 448.

1/7 times 64

So now our fractions look like this:

140
448
+
64
448

Step 2

Since our denominators match, we can add the numerators.

140 + 64 = 204

Now we have an answer.

204
448

Step 3

Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction?

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:

204
448
÷ 2 =
102
224

So far so good... let's try to divide by that number again.

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

102
224
÷ 2 =
51
112

So far so good... let's try to divide by that number again.

No good. So next you try the next prime number, which is 3...

No good. So next you try the next prime number, which is 5...

No good. So next you try the next prime number, which is 7...

No good. So next you try the next prime number, which is 11...

No good. So next you try the next prime number, which is 13...

No good. So next you try the next prime number, which is 17...

No good. So next you try the next prime number, which is 19...

No good. So next you try the next prime number, which is 23...

No good. So next you try the next prime number, which is 29...

No good. So next you try the next prime number, which is 31...

No good. So next you try the next prime number, which is 37...

No good. So next you try the next prime number, which is 41...

No good. So next you try the next prime number, which is 43...

No good. So next you try the next prime number, which is 47...

No good. So next you try the next prime number, which is 53...

No good. 53 is larger than 51. So we're done reducing.

And we're done! Here's the final answer to 20/64 + 1/7

20
64
+
1
7
=
51
112
© 2014 Randy Tayler