math help

What is 100/72 + 2/5?

What is 100/72 + 2/5?

Here's how we add

100
72
+
2
5

Step 1

Can you add yet? Nope! The denominators don't match. We need a common denominator. So next we take both denominators and multiply them. Next, take each numerator and multiply it by the denominator of the other term.

So, we multiply 100 by 5, and get 500, then we multiply 72 by 5 and get 360.

100/72 times 5

Now for the second term. You multiply 2 by 72, and get 144, then multiply 72 by 5 and get 360.

2/5 times 72

We now have a new problem, that looks like this:

500
360
+
144
360

Step 2

Since our denominators match, we can add the numerators.

500 + 144 = 644

Answer:

644
360

Step 3

Now, do we need to simplify this fraction?

First, we attempt to divide it by 2...

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

644
360
÷ 2 =
322
180

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:

322
180
÷ 2 =
161
90

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...

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. So next you try the next prime number, which is 41...

No good. So next you try the next prime number, which is 43...

No good. So next you try the next prime number, which is 47...

No good. So next you try the next prime number, which is 53...

No good. So next you try the next prime number, which is 59...

No good. So next you try the next prime number, which is 61...

No good. So next you try the next prime number, which is 67...

No good. So next you try the next prime number, which is 71...

No good. So next you try the next prime number, which is 73...

No good. So next you try the next prime number, which is 79...

No good. So next you try the next prime number, which is 83...

No good. So next you try the next prime number, which is 89...

No good. So next you try the next prime number, which is 97...

No good. 97 is larger than 90. So we're done reducing.

And we're done! Here's the final answer to 100/72 + 2/5

100
72
+
2
5
=
161
90
© 2014 Randy Tayler