u can only use the no. 4
it mus b 4 number 4.
u can add, subtract, multiply or divide, square root, square.
the idea is to use the above rule to make up a number.
for eg.
0 = 44-44 or
0 = 4+4-4-4
lets see how many numbers we can go 
i go 1st
0 = (4x4)-(4x4)
