1. Discount

• Discount = Marked Price – Sale Price
• Discount = (Discount % × Marked Price) / 100
• Sale Price = Marked Price – Discount

2. Cost Price (CP) with Overhead Expenses

• CP = Buying Price + Overhead Expenses

3. Sales Tax

• Sales Tax = (Tax % × Bill Amount) / 100
• Total Bill Amount = Bill Amount + Sales Tax

4. Goods and Services Tax (GST)

• GST = (GST % × Bill Amount) / 100
• Total Bill Amount = Bill Amount + GST

5. Compound Interest (CI)

(a) When Interest is Compounded Annually

• A = P(1 + r/100)ⁿ
• CI = A – P
• Where:
  • A = Final Amount
  • P = Principal Amount
  • r = Rate of Interest (%) per annum
  • n = Number of Years

b) When Interest is Compounded Half-Yearly

• A = P (1 + r/200)²ⁿ
• CI = A – P
• Since interest is compounded twice a year, we divide r by 2 and multiply n by 2.

(c) When Interest is Compounded Quarterly

• A = P (1 + r/400)⁴ⁿ
• CI = A – P
• Since interest is compounded four times a year, we divide r by 4 and multiply n by 4.

6. Depreciation Formula

• A = P (1 – r/100)ⁿ
• Where:
  • A = Value after depreciation
  • P = Initial Value (Original Price)
  • r = Rate of Depreciation (%)
  • n = Number of Years
•