(1) A cube with a volume of 5 is 125 cubic centimeters. Because the volume of a large cube is 9 1 cubic centimeter larger than that of a small cube, the volume of a large cube is 2 16 cubic centimeter, and the square of 2 16 is 6, so the side length of a large carton is 6 centimeters.

(2) because xy satisfies Y=√x- 1+√ 1-x+4, x= 1 is greater than or equal to 0, and Y=4.

So √xy=2

(3) Because √ 15 is a number greater than 3 and less than 4, and A is an integer part of √ 15, so a=3, and because B is a decimal part of √ 15, so b=√ 15-3, so A-B = 6.