Slabs can be used for decorating your house and can be used as fancy type of stairs but dont elevate as high as normal stairs.
Basically all of the solid and the liquid blocks, but they can't climb single slabs but they can climb double slabs.
for now you cant gust slabs
No, mobs will not spawn in water or ontop of half slabs.
No, but you could make one from your imagination with coloured wool blocks or stone slabs.
You can. You need to go to the crafting table and on the far right of the first page there are stairs and slabs that can be made.
Bricks can only be made into Brick Blocks, Stairs and Slabs.
bacon.
Non suspended concrete slabs sit on the ground directly. They are different from suspended slabs because suspended slabs are above the ground and are supported by beams.
You could build a cool building, it is also a crafting material for buttons, stone pressure plates, stone slabs, stone bricks, and redstone repeaters.
The best way to do this would be to use Too Many Items In-Game Inventory Editor, on the second page, there is a row or so of snow slabs with different thicknesses.
48+ breakages
The answer will vary slightly depending on assumptions: will the slabs have a space between them, and will you be cutting the slabs to fill fractions. 21 feet is equal to 14.2 of the 450 mm slabs. 19 feet is equal to 12.9 of the slabs. To complete the rectangular area, 14.2 x 12.9 = 183 slabs.