Follow thru each value of SCORE
The Proc Print output.

Example 3, with different data

ID    SCORE     GRADE    NOFORMAT

 1    F           F          0.0
 2        -1                -1.0
 3    A           A        101.0
 4    B           B         82.1
 5      89.1      B         89.1
 6         .                  .

In the first data line Score=0. The formatted value of SCORE and the GRADE are the same. Notice that NOFORMAT printed out as though the following was specified:
FORMAT NOFORMAT 5.1;
In the second data line Score = -1. The value is not included in the range specified in the VALUE statement. Thus, -1 has no associated label. In these cases, the internal value is printed as the formatted value.
In the third data line Score=101. The formatted value of SCORE and the GRADE are the same.
In the fourth data line Score=82.1. The value is not an integer. The formatted value of SCORE and the GRADE are the same. This is because the following WHEN is true.

       WHEN (80 LE SCORE LT 90) Grade='B';

and because the VALUE range includes the value 82.1.

            80-89  ='B'

In the fifth data line when Score=89.1. The value is not an integer. The formatted value of SCORE and the GRADE are not the same. This is because no VALUE range includes this value.

            80-89  ='B'
            90-HIGH='A';