The math club makes 35 bars of laundry soap a week and sells these at $20 each. This means that the total number of bars of laundry soap made in a 4 week month would be
4 × 35 = 140 bars
If the pupils found that 6 bars were destroyed by mice, the total number of bars of soap left would be
140 - 6 = 134 bars
Therefore, the total sale at the end of a four week month would be
