996 square feet X 1/3 foot = 332 cubic feet.
332 cft / 27 = 12.3 cubic yards
You will need 17.8 cubic yards of concrete.
10.67 Cubic Yards
10 yards
6.67 Cubic Yards
15 cubic yards
4.938 cubic yards.
concrete is sold in cubic yards in the united states. I hope you are using a 1/4 inch diameter reinforce mesh. 1680 / 81 = 20.74 cubic yards without subtracting the mesh volume.
You will need 17.8 cubic yards of concrete.
10.67 Cubic Yards
532.4074 yards of concrete, round up to 533 yards.
You'll need 3.53 cubic yards of cement.
6.94 Cubic Yards
3.6 cubic yards will be enough.
10 yards
6.67 Cubic Yards
15 cubic yards
15 cubic yards