What is the greatest number of 2 x 2 squares that will fit on a 9 x 9 square without any overlap, without going beyond the
9 x 9 square and without breaking up any of the 2 x 2 squares?

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?