math help

What is 87/100 + 3/12?

What is 87/100 + 3/12?

This is how to add

87
100
+
3
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 3 by 100, and get 300, then multiply 100 by 12 and get 1200.

3/12 times 100

The problem now has new fractions to add:

1044
1200
+
300
1200

Step 2

Since our denominators match, we can add the numerators.

1044 + 300 = 1344

This yields the answer

1344
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:

1344
1200
÷ 2 =
672
600

Now, try the same number again.

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

672
600
÷ 2 =
336
300

Now, try the same number again.

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

336
300
÷ 2 =
168
150

Now, try the same number again.

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

168
150
÷ 2 =
84
75

Now, try the same number again.

Nope. Try the next prime number, 3...

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

84
75
÷ 3 =
28
25

Now, try the same number again.

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...

No good. 29 is larger than 28. So we're done reducing.

Congratulations! Here's your final answer to 87/100 + 3/12

87
100
+
3
12
=
28
25
© 2014 Randy Tayler