math help

What is 20/64 + 5/9?

What is 20/64 + 5/9?

Here's how to add

20
64
+
5
9

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 20 by 9, and get 180, then we multiply 64 by 9 and get 576.

20/64 times 9

Do the same for the second term. We multiply 5 by 64, and get 320, then multiply 64 by 9 and get 576.

5/9 times 64

The problem now has new fractions to add:

180
576
+
320
576

Step 2

Since our denominators match, we can add the numerators.

180 + 320 = 500

This yields the answer

500
576

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:

500
576
÷ 2 =
250
288

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:

250
288
÷ 2 =
125
144

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. So next you try the next prime number, which is 59...

No good. So next you try the next prime number, which is 61...

No good. So next you try the next prime number, which is 67...

No good. So next you try the next prime number, which is 71...

No good. So next you try the next prime number, which is 73...

No good. So next you try the next prime number, which is 79...

No good. So next you try the next prime number, which is 83...

No good. So next you try the next prime number, which is 89...

No good. So next you try the next prime number, which is 97...

No good. So next you try the next prime number, which is 101...

No good. So next you try the next prime number, which is 103...

No good. So next you try the next prime number, which is 107...

No good. So next you try the next prime number, which is 109...

No good. So next you try the next prime number, which is 113...

No good. So next you try the next prime number, which is 127...

No good. 127 is larger than 125. So we're done reducing.

And we're done! Here's the final answer to 20/64 + 5/9

20
64
+
5
9
=
125
144
© 2014 Randy Tayler