math help

What is 3/24 + 2/5?

What is 3/24 + 2/5?

This is how to add

3
24
+
2
5

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 3 by 5, and get 15, then we multiply 24 by 5 and get 120.

3/24 times 5

Do the same for the second term. We multiply 2 by 24, and get 48, then multiply 24 by 5 and get 120.

2/5 times 24

The problem now has new fractions to add:

15
120
+
48
120

Step 2

Since our denominators match, we can add the numerators.

15 + 48 = 63

This yields the answer

63
120

Step 3

The last step is to reduce the fraction if we can.

To find out, we try dividing it by 2...

Nope. Try the next prime number, 3...

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

63
120
÷ 3 =
21
40

Now, try the same number again.

Nope. Try the next prime number, 5...

Nope. Try the next prime number, 7...

Nope. Try the next prime number, 11...

Nope. Try the next prime number, 13...

Nope. Try the next prime number, 17...

Nope. Try the next prime number, 19...

Nope. Try the next prime number, 23...

No good. 23 is larger than 21. So we're done reducing.

Congratulations! Here's your final answer to 3/24 + 2/5

3
24
+
2
5
=
21
40
© 2014 Randy Tayler