This lecture explains how to convert distance and time units by using multiplication or division with the correct conversion factor. When converting from bigger units to smaller ones (like kilometres to meters), we multiply, and when converting from smaller units to bigger ones (like meters to kilometres), we divide. It also highlights important rules such as “if the unit gets smaller, the number gets bigger” and vice versa. Students learn how to add and subtract measurements by converting them into the same unit, carrying over when needed, and always writing the final answer with proper units. Several solved examples show conversions between kilometres, meters, centimetres, millimetres, and how to calculate sums and differences in distance.