math help

What is 100/24 + 5/7?

What is 100/24 + 5/7?

This is how we add

100
24
+
5
7

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 100 by 7, and get 700, then we multiply 24 by 7 and get 168.

100/24 times 7

Do the same for the second term. We multiply 5 by 24, and get 120, then multiply 24 by 7 and get 168.

5/7 times 24

So now our fractions look like this:

700
168
+
120
168

Step 2

Since our denominators match, we can add the numerators.

700 + 120 = 820

So the answer is:

820
168

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:

820
168
÷ 2 =
410
84

Now, try the same number again.

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

410
84
÷ 2 =
205
42

Now, try the same number again.

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

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...

Nope. Try the next prime number, 29...

Nope. Try the next prime number, 31...

Nope. Try the next prime number, 37...

Nope. Try the next prime number, 41...

Nope. Try the next prime number, 43...

No good. 43 is larger than 42. So we're done reducing.

Congratulations! Here's your final answer to 100/24 + 5/7

100
24
+
5
7
=
205
42
© 2014 Randy Tayler