20 + 20 = 40 is not 40 when either one of the two terms is a negative or both.
-20 + 20 = 0 and -20 + -20 = -40
50 + 40 + 40 + 40 + 30 + 30 + 20 + 10 = 260
thinking is amazing
20 plus 20 equals 4020 plus 20 = 40
It is so very simple and quick to get the answer if you use the calculator that comes with your computer. So why not give it a try?
40 + (20%) = 48
the sum for 20 + 40 + 70 + 80 = 210
10 plus 20 plus 30plus 40 plus 50 equals 150 because 50 plus 40 equals 90 plus 30 =120+20= 140 then + 10 = 150
40...
the answer to 20 + 20 = 40
20+35+40+55+60+55+80=345
Of course!
These may help you answer your questions: 1, 2, 4, 5, 8, 10, 20 and 40.