🔵Length Conversions (km, m, cm)
The metric system uses powers of 10 for all conversions — making them easy with multiplication and division.
Key Conversions for Length:
- 1 km = 1,000 m (multiply by 1,000 to convert km to m)
- 1 m = 100 cm (multiply by 100 to convert m to cm)
- 1 km = 1,00,000 cm
Converting from larger to smaller unit: MULTIPLY.
Converting from smaller to larger unit: DIVIDE.
Memory trick: King Henry Died By Drinking Chocolate Milk — Kilo, Hecto, Deca, Base, Deci, Centi, Milli.
👀 See a worked example
🤖 Vidi's Key Points
- 1 km = 1,000 m; 1 m = 100 cm
- Larger to smaller unit: MULTIPLY
- Smaller to larger unit: DIVIDE
- Mixed measurements: convert all to the same unit, then add
🟢Weight and Capacity Conversions (kg, g, L, mL)
Weight (Mass):
1 kilogram (kg) = 1,000 grams (g)
Capacity:
1 litre (L) = 1,000 millilitres (mL)
Both use the same conversion factor: x 1,000 for the larger-to-smaller direction.
In Indian context: a bag of sugar = 1 kg = 1,000 g. A large water bottle = 1 L = 1,000 mL.
👀 See a worked example
🤖 Vidi's Key Points
- 1 kg = 1,000 g; 1 L = 1,000 mL — both use x 1,000
- To convert kg to g: multiply by 1,000
- To convert mL to L: divide by 1,000
- Mixed measurements: first convert to the smaller unit, then add
🟣Time Conversions
Time conversions do NOT follow powers of 10 — so we must memorize these relationships:
- 1 hour = 60 minutes
- 1 minute = 60 seconds
- 1 day = 24 hours
- 1 week = 7 days
To convert hours to minutes: multiply by 60.
To convert minutes to hours: divide by 60.
For elapsed time (how long something took): convert start and end to the same unit, then subtract.
👀 See a worked example
🤖 Vidi's Key Points
- 1 hour = 60 minutes (not 10 or 100!)
- 1 minute = 60 seconds; 1 day = 24 hours; 1 week = 7 days
- For elapsed time: find time from start to end
- Time conversions use x60 (larger to smaller) and /60 (smaller to larger)
🟡Mixed Measurement Word Problems
Many real-life problems combine different units or require multiple steps. Always:
- Step 1: Identify the units given and the unit needed
- Step 2: Convert all measurements to the same unit
- Step 3: Perform the required calculation
- Step 4: Express answer in appropriate unit
Common mistakes to avoid: forgetting to convert before adding, mixing up kg and g in the same calculation.
👀 See a worked example
🤖 Vidi's Key Points
- Always convert to the same unit before adding or subtracting
- Large to small: multiply; Small to large: divide
- For time: hours and minutes must be handled separately before adding
- Always check if your answer is in the correct unit
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