Question

Why does binary addition have a rule for 1 + 1 + 1 if only two numbers are being added together?

Answer 1

Answer:

See below

Explanation:

Because sometimes you have to 'carry' a 1 over to the ext column when adding two binary numbers

Example :

 1 1 1

+1 1 1    <==== starting in the first R column add  1 + 1  to get 0 and carry 1

                then the next column you will add   1 + 1 + 1  = 1   and carry 1 again

                    then 1 + 1 + 1= 1  and carry 1 again (to column 4)  to get

1   1  1 0