Addendum to the answer…Shruti Mittal sent 6 more correct asnwers – Well done Shruti!

            (-1*2)-3-4-5+6*7+8*9=100

          1+(2*3)+(4*5)+(-6+7)+(8*9)

          1*(2+3)*4*5*(6-7)*(8-9)

          1*(2+3)*Sqrt(4)*5*{-[(6-7)+(CubeRoot(8)-Sqrt(9)]}

          1*2*(3+4)*5+6+7+8+9

           (1+2+3+4)*5*{(-6+7)+(-8+9)}

Surprisingly I got only one correct answer, from Ishir Gupta (Bangalore) – well done Ishir. I am assuming the rest of the folks found it too simple to respond 🙂

Here is the answer from Ishir:

(1 * 2  + 3 ) * 4  * 5  + 6 – 7 – 8 + 9 = 100

For a change, since the puzzle was contributed by someone else, I got a chance to work on it as well, and found the following answers:

1+2+3+4+5+6+7+ 8*9

1 – 2 + (3+4)*5 + 6*7 + 8-9

1 + (2*3*4*5)/6 + 7 + 8*9

Sqrt (-1+2+3) + (4!*5) + 6 – 7 – 8 – 9

-1 + 2*3*4 + 5*6 + 7*8 – 9

If any of you find more, please do let me know, I will also pass it on to Alok Mittal, who is trying to collect 12 unique answers to this puzzle!

Hope you enjoyed this.