1-20, 25, 30-100
Use the calculator and column buttons to create a boolean formula (or type one in directly), indicating which rows should be selected. All the rows that satisfy the condition (expression evaluates to TRUE, or not equal to zero) will be selected.
When the "Select" button (or <Return> key) is pressed, fv will highlight the selected rows in the table.
See the calculator help page for information on how to specify the conditional expression.