math help

What is 80/2 + 5/11?

What is 80/2 + 5/11?

Here's how to add

80
2
+
5
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 80 by 11, and get 880, then we multiply 2 by 11 and get 22.

80/2 times 11

Do the same for the second term. We multiply 5 by 2, and get 10, then multiply 2 by 11 and get 22.

5/11 times 2

The problem now has new fractions to add:

880
22
+
10
22

Step 2

Since our denominators match, we can add the numerators.

880 + 10 = 890

This yields the answer

890
22

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:

890
22
÷ 2 =
445
11

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. 13 is larger than 11. So we're done reducing.

And we're done! Here's the final answer to 80/2 + 5/11

80
2
+
5
11
=
445
11
© 2014 Randy Tayler