28, but that's two digits.
in ones digit arithmetic to define a+b you take the integer a+b and drop all but the one's digit (same for a x b). 1+2+3+4+5+6+7=8 because you drop all but the one's digit.
28
This will be in binary arithmetic, i.e. base 2 arithmetic.
Not in normal arithmetic.
3
65 x 11 = 715 This represents 7 x 100 plus 1 x 10 plus 5 x 1. The one's digit is therefore 5.
In normal arithmetic it is equal to 2
When you are working in binary arithmetic.
Because "plus" has a specific meaning in arithmetic and it is not concatenation.
1+0+3 is the digit sum of 103
There are two situations in which 1 plus 1 equals 10. One is when counting in binary arithmetic so that numbers are represented in 2 and powers of 2. The other is that "plus" is defined differently.
1 + 1 is not an equation as it is not telling us that one thing equates to another. 1 + 1 = 2 is an equation and hopefully the answer you are looking for.