1. Create a Solver model that sets the value of cell D25 to 0 (indicating that all shifts are covered) by changing the values in the range D5:J19 under the following constraints:
   1. Add a binary constraint to force every value in the range D5:J19 to be either a 0 or a 1.
   2. Add a constraint to limit the total hours worked by each fulltime employee to less than or equal to 40.
   3. Add a constraint to limit the total hours worked by each parttime employee to less than or equal to 24.
   4. Add a constraint to require that the difference values in the range D23:J23 all equal 0.
   5. Based on the entries in the range C5:C19, add constraints so that employees are not scheduled to work shifts on days when they are unavailable to work.