Comparing Quantities – Formulas & Notes (Class 6
to 12)
1. Ratio (Class 6–7)
• Ratio of a to b = a : b
• Equivalent ratios: Multiply or divide both terms by same number
• Example: 2:3 = 4:6 = 6:9
2. Percentage
• Percentage = (Part / Whole) × 100
• x% = x/100
• To convert fraction to percentage: multiply by 100
• To convert percentage to fraction: divide by 100
3. Increase and Decrease in Percentage
• Percentage Increase = (Increase / Original value) × 100
• Percentage Decrease = (Decrease / Original value) × 100
4. Profit and Loss
• Cost Price (CP): Price at which an article is bought
• Selling Price (SP): Price at which an article is sold
• Profit = SP – CP
• Loss = CP – SP
• Profit % = (Profit / CP) × 100
• Loss % = (Loss / CP) × 100
5. Discount
• Marked Price (MP): Price written on the article
• Discount = MP – SP
• Discount % = (Discount / MP) × 100
6. Simple Interest (SI)
• SI = (P × R × T) / 100
• P = Principal
• R = Rate of interest per year
• T = Time in years
to 12)
1. Ratio (Class 6–7)
• Ratio of a to b = a : b
• Equivalent ratios: Multiply or divide both terms by same number
• Example: 2:3 = 4:6 = 6:9
2. Percentage
• Percentage = (Part / Whole) × 100
• x% = x/100
• To convert fraction to percentage: multiply by 100
• To convert percentage to fraction: divide by 100
3. Increase and Decrease in Percentage
• Percentage Increase = (Increase / Original value) × 100
• Percentage Decrease = (Decrease / Original value) × 100
4. Profit and Loss
• Cost Price (CP): Price at which an article is bought
• Selling Price (SP): Price at which an article is sold
• Profit = SP – CP
• Loss = CP – SP
• Profit % = (Profit / CP) × 100
• Loss % = (Loss / CP) × 100
5. Discount
• Marked Price (MP): Price written on the article
• Discount = MP – SP
• Discount % = (Discount / MP) × 100
6. Simple Interest (SI)
• SI = (P × R × T) / 100
• P = Principal
• R = Rate of interest per year
• T = Time in years
