math help

What is 20/64 + 4/10?

What is 20/64 + 4/10?

Here's how to add

20
64
+
4
10

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 10, and get 200, then we multiply 64 by 10 and get 640.

20/64 times 10

Do the same for the second term. We multiply 4 by 64, and get 256, then multiply 64 by 10 and get 640.

4/10 times 64

The problem now has new fractions to add:

200
640
+
256
640

Step 2

Since our denominators match, we can add the numerators.

200 + 256 = 456

This yields the answer

456
640

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:

456
640
÷ 2 =
228
320

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:

228
320
÷ 2 =
114
160

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:

114
160
÷ 2 =
57
80

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. 59 is larger than 57. So we're done reducing.

And we're done! Here's the final answer to 20/64 + 4/10

20
64
+
4
10
=
57
80
© 2014 Randy Tayler