Hi,
Area of each MS slab panel is 0.9x0.6=0.54 Sqm
Slab area = 4000Sft=373Sqm = 374/0.54= 691Nos of MS slab panels
Acrospan =691/5=138 Nos
Total Props for 4000 Sft slab = 138x 2.5 =345 Nos
Hope this information best of my knowledge all the Best Reddy Sir.