math help

What is 20/64 + 3/12?

What is 20/64 + 3/12?

Let's add

20
64
+
3
12

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 20 by 12, and get 240, then we multiply 64 by 12 and get 768.

20/64 times 12

Now for the second term. You multiply 3 by 64, and get 192, then multiply 64 by 12 and get 768.

3/12 times 64

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

240
768
+
192
768

Step 2

Since our denominators match, we can add the numerators.

240 + 192 = 432

Answer:

432
768

Step 3

Now, do we need to simplify this fraction?

First, we attempt to divide it by 2...

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

432
768
÷ 2 =
216
384

Let's try dividing by that again...

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

216
384
÷ 2 =
108
192

Let's try dividing by that again...

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

108
192
÷ 2 =
54
96

Let's try dividing by that again...

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

54
96
÷ 2 =
27
48

Let's try dividing by that again...

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

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

27
48
÷ 3 =
9
16

Let's try dividing by that again...

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...

No good. 11 is larger than 9. So we're done reducing.

There you have it! Here's the final answer to 20/64 + 3/12

20
64
+
3
12
=
9
16
© 2014 Randy Tayler