| # | Category / Concept | Formula / Rule |
| 1 | Gain (Profit) | $Gain = S.P. – C.P.$ |
| 2 | Loss | $Loss = C.P. – S.P.$ |
| 3 | Baseline Rule | Loss or Gain is always reckoned on Cost Price (C.P.). |
| 4 | Gain Percentage | $Gain \% = \left( \frac{Gain \times 100}{C.P.} \right)$ |
| 5 | Loss Percentage | $Loss \% = \left( \frac{Loss \times 100}{C.P.} \right)$ |
| 6 | Selling Price (Gain) | $S.P. = \frac{(100 + Gain \%)}{100} \times C.P.$ |
| 7 | Selling Price (Loss) | $S.P. = \frac{(100 – Loss \%)}{100} \times C.P.$ |
| 8 | Cost Price (Gain) | $C.P. = \frac{100}{(100 + Gain \%)} \times S.P.$ |
| 9 | Cost Price (Loss) | $C.P. = \frac{100}{(100 – Loss \%)} \times S.P.$ |
| 10 | Gain Shortcut | If sold at a gain of 35%, then $S.P. = 135\% \text{ of } C.P.$ |
| 11 | Loss Shortcut | If sold at a loss of 35%, then $S.P. = 65\% \text{ of } C.P.$ |
| 12 | Common Gain & Loss | When selling two items (one at $x\%$ gain and one at $x\%$ loss), the seller always incurs a loss: $Loss \% = \left( \frac{x}{10} \right)^2$ |
| 13 | False Weights | $Gain \% = \left[ \frac{Error}{(True\ Value) – (Error)} \times 100 \right] \%$ |
Master In Technology,
