math help

What is 100/72 + 1/5?

What is 100/72 + 1/5?

This is how we add

100
72
+
1
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 100 by 5, and get 500, then we multiply 72 by 5 and get 360.

100/72 times 5

Do the same for the second term. We multiply 1 by 72, and get 72, then multiply 72 by 5 and get 360.

1/5 times 72

The problem now has new fractions to add:

500
360
+
72
360

Step 2

Since our denominators match, we can add the numerators.

500 + 72 = 572

This yields the answer

572
360

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:

572
360
÷ 2 =
286
180

Now, try the same number again.

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

286
180
÷ 2 =
143
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 + 1/5

100
72
+
1
5
=
143
90
© 2014 Randy Tayler