A couple of ancient civilizations invented number systems with place values. The oldest was the Mayan system with 60 at its base, around 3400 BC. The Egyptians invented a 10 base system in 3100 BC. The modern place value system also has 10 as its compression figure.
The national average cost for painting new construction interiors is $3.65 per sq. ft. (heated floor space) that does not include casework like cabinets vanities etc. Repaints do not require the same volume of paint but do have a different set of challenges.
This will get you an approximate labor cost if there's not a lot of repair work needed. A 12x12x8 room will have about 384 square feet of wall space. 384' x $.70 = $270 (268.80) Paint for this room will run about $.20 per square foot of wall space.This will add about $70 to the price above if using a Benjamin Moore high quality paint. Then, sundries, or supplies will be added. They typical cost for this will be about $50 ($.13 per square foot) for a typical room.The prices that are listed for paint and sundries will vary and also are purchased at a discount by the contractor The total cost for painting an interior will run about $1.02 per square foot (about $390 for the for a 12x12 room) of wall space being painted.