Important formulas:
1. Per cent (%) = Per hundred
2. Fractional numbers to percentage: multiply the fraction by 100.
3. Decimal numbers to percentage: multiply the fraction by 100.
4. 
5. Profit = SP (selling price) - CP (cost price)
6. Profit percent = \( \frac{Profit}{CP} \) x 100
7. Loss = CP (cost price) - SP (selling price)
8. Loss percent = \( \frac{Loss}{CP} \) x 100
9. I = \( \frac{P \times R \times T }{100} \)
Where: I is Simple Interest, P is Principal amount, R is rate of interest & T is time.
10. Amount = P + I