math help

What is 3/24 + 7/10?

What is 3/24 + 7/10?

This is how you add

3
24
+
7
10

Step 1

We can't add two fractions with different denominators (the bottom number). So you need to get a common denominator - both bottom numbers need to match. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator.

So we multiply 3 by 10, and get 30, then we multiply 24 by 10 and get 240.

3/24 times 10

Do the same for the second term. We multiply 7 by 24, and get 168, then multiply 24 by 10 and get 240.

7/10 times 24

So now our fractions look like this:

30
240
+
168
240

Step 2

Since our denominators match, we can add the numerators.

30 + 168 = 198

Now we have an answer.

198
240

Step 3

Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction?

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:

198
240
÷ 2 =
99
120

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:

99
120
÷ 3 =
33
40

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. So next you try the next prime number, which is 7...

No good. So next you try the next prime number, which is 11...

No good. So next you try the next prime number, which is 13...

No good. So next you try the next prime number, which is 17...

No good. So next you try the next prime number, which is 19...

No good. So next you try the next prime number, which is 23...

No good. So next you try the next prime number, which is 29...

No good. So next you try the next prime number, which is 31...

No good. So next you try the next prime number, which is 37...

No good. 37 is larger than 33. So we're done reducing.

And we're done! Here's the final answer to 3/24 + 7/10

3
24
+
7
10
=
33
40
© 2014 Randy Tayler