315
18-ft x 11-ft = 198 square ft
assuming standard sheet is 4 x 8 = 32 square feet roof is 29 x 45 = 1305 sq ft you need 1305/32 = 41 sheets
960 sq. ft.
16-ft x 70-ft = 1,120 square feet
960 square feet.
310.5 sq ft
100 sq ft = 1 square.
One square = 100 sq ft of roof area.
943 sq ft 9 and 1/2 squares of roofing
When talking about the area of a roof, remember that it is not the same as the square footage of the structure. For example a 20 x 30' building with a 12" overhang and a 4/12 pitch will have 736 sq ft of roof vs only 600 sq ft of slab. One square of shingles covers 100 square feet. 15 year shingles come 3 bundles to a square. 25 year come 4 bundles to a square.
A Standard roll of 30lb felt will cover 2 square or 200 sq ft
You'll need 50*28 = 1400 square feet
If the dimensions are in feet then 16 times 16 = 256 square feet
315
3 bundles to a square and 100 sq. ft. in a square, so 3 times 16 equals 48. Depending on how much roof edge and peak add a couple bundles for starter strip and the cap.
Standard grade, 3 bundles to a square. 1 square= 100 sq. ft. With the starter row and the cap, 5 sq. will probably make it.