Determine how many yards are in 20kmĀ 

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 \cdot \frac{1000m}{1km} \cdot \frac{3.2808 ft}{1 m} \cdot \frac{1 yard}{3 ft} = 21872 yards

Convert 33^\circ into Kelvin:

conversion is not based on multiplication but addition.

Use the conversion formula

Kelvin = celsius + 273.15 = 306.15 K