1. The problem asks: Which number represents "monthly" in a 5-day workweek coding system? 2. In a 5-day workweek, the number of workdays in a month is typically calculated by multiplying the number of weeks in a month by 5. 3. Since there are about 4 weeks in a month, the total workdays in a month are: $$5 \times 4 = 20$$ 4. Therefore, the number that means "monthly" in this coding system is 20. 5. The other options (4, 5, 30) do not correspond to the number of workdays in a month under a 5-day workweek system.