math help

What is 100/72 + 2/10?

What is 100/72 + 2/10?

This is how you add

100
72
+
2
10

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 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 2 by 72, and get 144, then multiply 72 by 10 and get 720.

2/10 times 72

So now our fractions look like this:

1000
720
+
144
720

Step 2

Since our denominators match, we can add the numerators.

1000 + 144 = 1144

So the answer is:

1144
720

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:

1144
720
÷ 2 =
572
360

Now, try the same number again.

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 + 2/10

100
72
+
2
10
=
143
90
© 2014 Randy Tayler