math help

What is 80/2 + 4/12?

What is 80/2 + 4/12?

Here's how to add

80
2
+
4
12

Step 1

We have to make sure the denominators are equal.

Since 2 is evenly divided by 12, we can multiply just one term to get a common denominator.

Multiply 80 by 6, and get 480, then we multiply 2 by 6 and get 12.

80/2 times 6

The problem now has new fractions to add:

480
12
+
4
12

Step 2

Since our denominators match, we can add the numerators.

480 + 4 = 484

This yields the answer

484
12

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:

484
12
÷ 2 =
242
6

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:

242
6
÷ 2 =
121
3

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. 5 is larger than 3. So we're done reducing.

And we're done! Here's the final answer to 80/2 + 4/12

80
2
+
4
12
=
121
3
© 2014 Randy Tayler