math help

What is 25/15 + 2/12?

What is 25/15 + 2/12?

Here's how you add

25
15
+
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 25 by 12, and get 300, then we multiply 15 by 12 and get 180.

25/15 times 12

Do the same for the second term. We multiply 2 by 15, and get 30, then multiply 15 by 12 and get 180.

2/12 times 15

The problem now has new fractions to add:

300
180
+
30
180

Step 2

Since our denominators match, we can add the numerators.

300 + 30 = 330

The sum we get is

330
180

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:

330
180
÷ 2 =
165
90

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:

165
90
÷ 3 =
55
30

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:

55
30
÷ 5 =
11
6

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 7...

No good. 7 is larger than 6. So we're done reducing.

There you have it! Here's the final answer to 25/15 + 2/12

25
15
+
2
12
=
11
6
© 2014 Randy Tayler