2
It is how 2 is defined so it is not an illusion.
Really it's 6 1/2
no if 1 plus 1 equals 2 then 2 plus 2 equals 4.
1 plus 3 equals four. You should really be asking better questions on Wikianswers.
4
1^2 + 1^2 + 1^2 + 1^2 + 1^2 + 1^2 = 1 + 1 + 1 + 1 + 1 + 1 = 5
One plus one is two. It can be expressed mathematically as 1+1 = 2.
1+2+3+4=10 The formula for adding consecutive numbers is n*(n+1)/2. This could be done easily as mental math, on paper or using a calculator.
It equals 7
30. 2+3+5=10, 4+6=10, and 2+4+1+1+2=10.
1/2 + 1/2 + 1/2 + 1/2 = 2 2 is four halves.