math help

What is 87/100 + 7/12?

What is 87/100 + 7/12?

This is how we add

87
100
+
7
12

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 87 by 12, and get 1044, then we multiply 100 by 12 and get 1200.

87/100 times 12

Do the same for the second term. We multiply 7 by 100, and get 700, then multiply 100 by 12 and get 1200.

7/12 times 100

The problem now has new fractions to add:

1044
1200
+
700
1200

Step 2

Since our denominators match, we can add the numerators.

1044 + 700 = 1744

The sum we get is

1744
1200

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:

1744
1200
÷ 2 =
872
600

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:

872
600
÷ 2 =
436
300

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:

436
300
÷ 2 =
218
150

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:

218
150
÷ 2 =
109
75

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. 79 is larger than 75. So we're done reducing.

And we're done! Here's the final answer to 87/100 + 7/12

87
100
+
7
12
=
109
75
© 2014 Randy Tayler