math help

What is 78/10 + 2/12?

What is 78/10 + 2/12?

Here's how we add

78
10
+
2
12

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 78 by 12, and get 936, then we multiply 10 by 12 and get 120.

78/10 times 12

Do the same for the second term. We multiply 2 by 10, and get 20, then multiply 10 by 12 and get 120.

2/12 times 10

The problem now has new fractions to add:

936
120
+
20
120

Step 2

Since our denominators match, we can add the numerators.

936 + 20 = 956

The sum we get is

956
120

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:

956
120
÷ 2 =
478
60

Let's try dividing by that again...

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

478
60
÷ 2 =
239
30

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...

No good. 31 is larger than 30. So we're done reducing.

There you have it! Here's the final answer to 78/10 + 2/12

78
10
+
2
12
=
239
30
© 2014 Randy Tayler