math help

What is 20/64 + 1/5?

What is 20/64 + 1/5?

This is how to add

20
64
+
1
5

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 5, and get 100, then we multiply 64 by 5 and get 320.

20/64 times 5

Do the same for the second term. We multiply 1 by 64, and get 64, then multiply 64 by 5 and get 320.

1/5 times 64

The problem now has new fractions to add:

100
320
+
64
320

Step 2

Since our denominators match, we can add the numerators.

100 + 64 = 164

This yields the answer

164
320

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:

164
320
÷ 2 =
82
160

Let's try dividing by that again...

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

82
160
÷ 2 =
41
80

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 3...

Nope! So now we try the next greatest prime number, 5...

Nope! So now we try the next greatest prime number, 7...

Nope! So now we try the next greatest prime number, 11...

Nope! So now we try the next greatest prime number, 13...

Nope! So now we try the next greatest prime number, 17...

Nope! So now we try the next greatest prime number, 19...

Nope! So now we try the next greatest prime number, 23...

Nope! So now we try the next greatest prime number, 29...

Nope! So now we try the next greatest prime number, 31...

Nope! So now we try the next greatest prime number, 37...

Nope! So now we try the next greatest prime number, 41...

Nope! So now we try the next greatest prime number, 43...

No good. 43 is larger than 41. So we're done reducing.

There you have it! Here's the final answer to 20/64 + 1/5

20
64
+
1
5
=
41
80
© 2014 Randy Tayler