math help

What is 78/10 + 7/11?

What is 78/10 + 7/11?

Let's add

78
10
+
7
11

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 78 by 11, and get 858, then we multiply 10 by 11 and get 110.

78/10 times 11

Do the same for the second term. We multiply 7 by 10, and get 70, then multiply 10 by 11 and get 110.

7/11 times 10

The problem now has new fractions to add:

858
110
+
70
110

Step 2

Since our denominators match, we can add the numerators.

858 + 70 = 928

This yields the answer

928
110

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:

928
110
÷ 2 =
464
55

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...

No good. 59 is larger than 55. So we're done reducing.

Congratulations! Here's your final answer to 78/10 + 7/11

78
10
+
7
11
=
464
55
© 2014 Randy Tayler