Question 123844
To form the greatest product, you want the largest number to be in the hundreds place and you want the next two numbers to be in the other multiplicand.  That gives us 721 X 54.

To get the largest quotient, you need the denominator to be as small as possible and the numerator to be as large as possible.  The smallest three-digit number that can be formed is 124, and the largest two digit number is 75, so 75/124.

The b part is just the opposite.  For the smallest product, you want the smallest numbers in the left-most positions, 147 X 25 gives a smaller result than 157 X 24.  For the smallest quotient, maximize the size of the denominator and minimize the size of the numerator 12/754