1. Let's start by stating the problem: Consumer arithmetic involves calculations related to buying and selling goods, including concepts like discounts, profit, loss, cost price, and selling price. 2. Important formulas used in consumer arithmetic include: - Profit = Selling Price (SP) - Cost Price (CP) - Loss = Cost Price (CP) - Selling Price (SP) - Profit Percentage = \frac{Profit}{Cost Price} \times 100 - Loss Percentage = \frac{Loss}{Cost Price} \times 100 - Selling Price after Discount = Marked Price - Discount 3. Key rules to remember: - If SP > CP, there is a profit. - If SP < CP, there is a loss. - Discounts reduce the selling price. 4. Example: Suppose an item costs $100 (CP) and is sold for $120 (SP). - Profit = $120 - $100 = $20 - Profit Percentage = \frac{20}{100} \times 100 = 20\% 5. Another example: An item marked at $150 is sold with a 10% discount. - Discount = 10\% of $150 = $15 - Selling Price = $150 - $15 = $135 6. These calculations help consumers and sellers understand pricing, savings, and earnings clearly. This explanation covers the basics of consumer arithmetic with formulas and examples to aid understanding.