Psuedocode:
1) Get an input value, verify that it is a number and if so, say if even or odd
get input value1
if (value1 is a number)
     if(value1 is odd)
        display number is odd
    else
         display number is even
else
   display value1 is not a number

2) get grade input, verify that is valid for a grade, and translate to a letter grade
get input value2
if(value2 is a number)
   if(value2 is less than 0 OR greater than 100)
      display error message 'number has to be between 0-thru-100'
   else
      Case based on value2
         Case > 89
             display "Grade = A"
         Case > 79
             display "Grade = B"
         Case > 69
             display "Grade = C"
         Case > 59
             display "Grade = D"
         Default
             display "Grade = F"
      End Case  
else
  display error message that value2 has to be numeric

TEST PLAN for #1
Action                  Expect Result                                                What you actually got
Enter odd number 23     Message "Number is odd"
Enter even number 68    Message "Number is even"
Enter odd number 101    Message "Number is odd"
Enter even number 102   Message "Number is even"
Enter odd number -9     Message "Number is odd"
Enter even number -8    Message "Number is even" 
Enter abc               Message error message "Input must be numeric"

TEST PLAN for #2
Action                  Expect Result                                               What you actually got
Enter number 23         Grade F
Enter number 59         Grade F
Enter number 60         Grade D
Enter number 68         Grade D
Enter number 69         Grade D
Enter number 79         Grade B
Enter number 86         Grade B
Enter number 89         Grade B
Enter number 70         Grade C
Enter number 78         Grade C
Enter number 79         Grade C
Enter number 90         Grade A
Enter number 92         Grade A
Enter number 100        Grade A
Enter odd number 101    Message error message "Number must be between 0 and 100"
Enter even number 102   Message error message "Number must be between 0 and 100"
Enter odd number -9     Message error message "Number must be between 0 and 100"
Enter even number -8    Message error message "Number must be between 0 and 100"
Enter abc               Message error message "Input must be numeric"