Evaluate the following sum:
1 – 4 + 9 – 16 + … + 99^2 – 100^2
1 2 3 4 5 6 7 8 9 = 100 Challenge: Place + and - math symbols between the numbers above to make the equation true. Use + and - a total of three times. Do not rearrange the numbers.
If 1-3+4=100, 4-6+9=999, 2-6+7=879 then 3-3+6=???
The digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 can be arranged into an addition sum to add up to almost any total, except that nobody has yet found a way to add up to 1984. However 9 digits can equal 1984 by an addition sum. Which digit is omitted?
