Gain or loss is always reckoned on the ..........

Answer

To answer the question "Gain or loss is always reckoned on the ..........", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Gain and Loss**:
- Gain or loss refers to the profit or deficit incurred when selling a product. It is essential to identify the basis on which this calculation is made.

2. **Identifying the Key Term**:
- The key term in the context of profit and loss is "cost price". The cost price is the amount paid to acquire a product before selling it.

3. **Calculating Gain or Loss**:
- Gain or loss is calculated by comparing the selling price (SP) with the cost price (CP).
- The formula for gain is:
\[ \text{Gain} = \text{Selling Price} - \text{Cost Price} \]
- The formula for loss is:
\[ \text{Loss} = \text{Cost Price} - \text{Selling Price} \]

4. **Conclusion**:
- Therefore, gain or loss is always reckoned on the **cost price**.

### Final Answer:
Gain or loss is always reckoned on the **cost price**.

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