math help

What is 4/40 + 6/12?

What is 4/40 + 6/12?

This is how to add

4
40
+
6
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 4 by 12, and get 48, then we multiply 40 by 12 and get 480.

4/40 times 12

Do the same for the second term. We multiply 6 by 40, and get 240, then multiply 40 by 12 and get 480.

6/12 times 40

The problem now has new fractions to add:

48
480
+
240
480

Step 2

Since our denominators match, we can add the numerators.

48 + 240 = 288

The sum we get is

288
480

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:

288
480
÷ 2 =
144
240

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:

144
240
÷ 2 =
72
120

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:

72
120
÷ 2 =
36
60

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:

36
60
÷ 2 =
18
30

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:

18
30
÷ 2 =
9
15

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...

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

9
15
÷ 3 =
3
5

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 5...

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

And we're done! Here's the final answer to 4/40 + 6/12

4
40
+
6
12
=
3
5
© 2014 Randy Tayler