math help

What is 15/60 + 4/8?

What is 15/60 + 4/8?

This is how we add

15
60
+
4
8

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 15 by 8, and get 120, then we multiply 60 by 8 and get 480.

15/60 times 8

Now for the second term. You multiply 4 by 60, and get 240, then multiply 60 by 8 and get 480.

4/8 times 60

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

120
480
+
240
480

Step 2

Since our denominators match, we can add the numerators.

120 + 240 = 360

That gives us the sum, which is

360
480

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:

360
480
÷ 2 =
180
240

Let's try dividing by that again...

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

180
240
÷ 2 =
90
120

Let's try dividing by that again...

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

90
120
÷ 2 =
45
60

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:

45
60
÷ 3 =
15
20

Let's try dividing by that again...

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

Are both the numerator and the denominator evenly divisible by 5? Yes! So we reduce it:

15
20
÷ 5 =
3
4

Let's try dividing by that again...

No good. 5 is larger than 3. So we're done reducing.

There you have it! Here's the final answer to 15/60 + 4/8

15
60
+
4
8
=
3
4
© 2014 Randy Tayler