math help

What is 100/72 + 5/9?

What is 100/72 + 5/9?

Here's how we add

100
72
+
5
9

Step 1

Now we need to make our denominators match.

Since 9 is evenly divided by 72, we can multiply just one term to get a common denominator.

Multiply 5 by 8, and get 40, then we multiply 9 by 8 and get 72.

5/9 times 8

The problem now has new fractions to add:

100
72
+
40
72

Step 2

Since our denominators match, we can add the numerators.

100 + 40 = 140

This yields the answer

140
72

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:

140
72
÷ 2 =
70
36

Let's try dividing by that again...

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

70
36
÷ 2 =
35
18

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 3...

Nope! So now we try the next greatest prime number, 5...

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

Nope! So now we try the next greatest prime number, 11...

Nope! So now we try the next greatest prime number, 13...

Nope! So now we try the next greatest prime number, 17...

Nope! So now we try the next greatest prime number, 19...

No good. 19 is larger than 18. So we're done reducing.

There you have it! Here's the final answer to 100/72 + 5/9

100
72
+
5
9
=
35
18
© 2014 Randy Tayler