Perform the following arithmetic operations and apply rounding and indicate the corresponding number of significant figures in your answer.

a)   350 000 - 5,0 x 10⁵⁺             

b)  243,18  +  5,2 x 10^-1      

 c)   83,400 / 3,8 x 10²             

 d)  (4,08  x  10³)  X  (3,531  x  10⁴)