math help

What is 100/72 + 8/10?

What is 100/72 + 8/10?

Let's add

100
72
+
8
10

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 100 by 10, and get 1000, then we multiply 72 by 10 and get 720.

100/72 times 10

Do the same for the second term. We multiply 8 by 72, and get 576, then multiply 72 by 10 and get 720.

8/10 times 72

The problem now has new fractions to add:

1000
720
+
576
720

Step 2

Since our denominators match, we can add the numerators.

1000 + 576 = 1576

The sum we get is

1576
720

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:

1576
720
÷ 2 =
788
360

Now, try the same number again.

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

788
360
÷ 2 =
394
180

Now, try the same number again.

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

394
180
÷ 2 =
197
90

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...

Nope. Try the next prime number, 47...

Nope. Try the next prime number, 53...

Nope. Try the next prime number, 59...

Nope. Try the next prime number, 61...

Nope. Try the next prime number, 67...

Nope. Try the next prime number, 71...

Nope. Try the next prime number, 73...

Nope. Try the next prime number, 79...

Nope. Try the next prime number, 83...

Nope. Try the next prime number, 89...

Nope. Try the next prime number, 97...

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

Congratulations! Here's your final answer to 100/72 + 8/10

100
72
+
8
10
=
197
90
© 2014 Randy Tayler