math help

What is 64/16 + 4/9?

What is 64/16 + 4/9?

This is how you add

64
16
+
4
9

Step 1

We still have different denominators (bottom numbers), though, so we need to get a common denominator. This will make the bottom numbers match. Multiply the denominators together first. Now, multiply each numerator by the other term's denominator.

Now we multiply 64 by 9, and get 576, then we multiply 16 by 9 and get 144.

64/16 times 9

Now for the second term. You multiply 4 by 16, and get 64, then multiply 16 by 9 and get 144.

4/9 times 16

This gives us a new problem that looks like so:

576
144
+
64
144

Step 2

Since our denominators match, we can add the numerators.

576 + 64 = 640

So what's the answer so far?

640
144

Step 3

Can this fraction be reduced?

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

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

640
144
÷ 2 =
320
72

Let's try dividing by that again...

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

320
72
÷ 2 =
160
36

Let's try dividing by that again...

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

160
36
÷ 2 =
80
18

Let's try dividing by that again...

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

80
18
÷ 2 =
40
9

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...

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

There you have it! Here's the final answer to 64/16 + 4/9

64
16
+
4
9
=
40
9
© 2014 Randy Tayler