Determine how many yards are in 20km
Use conversion fractions:
Conversion fractions contain equivalent numbers in the numerator and denominator.
Equivalent numbers:
1 km = 1,000 m
3 ft – 1 yard
1 m – 3.2808 ft
These numbers are placed into fractions so that the existing units will cancel and only the desired units are left.
Sometimes multiple conversion fractions are needed
20km 
yards
Convert 33
into Kelvin:
conversion is not based on multiplication but addition.
Use the conversion formula
Kelvin = celsius + 273.15 = 306.15 K