Explanation:
Know the essential metric conversions by heart: 1 cm = 10 mm, 1 m = 100 cm, 1 km = 1000 m, 1 kg = 1000 g, 1 tonne = 1000 kg, and 1 litre = 1000 ml = 1000 cm³. Multiply when changing from a larger unit to a smaller unit; divide when changing from a smaller unit to a larger unit.
For time, remember there are 60 minutes in 1 hour (so 0.25 hours = 15 mins, 0.5 hours = 30 mins, 0.75 hours = 45 mins). For area and volume conversions, square or cube the length conversion factor (e.g. 1 m² = 100² cm² = 10,000 cm²).
Example 1: Convert:
(a) 3.45 kg into grams
(b) 2 hours 24 minutes into hours (as a decimal)
Solution:
(a) 3.45 × 1000 = 3450 g
(b) 24 mins = 2460 hrs = 0.4 hours
2 + 0.4 = 2.4 hours
Answer: (a) 3450 g (b) 2.4 hours
Example 2: Convert 4.5 m² into cm².
Solution:
Length conversion: 1 m = 100 cm
Area conversion: 1 m² = 100 × 100 = 10,000 cm²
4.5 × 10,000 = 45,000 cm²
Answer: 45,000 cm²
