In the introduction of per unit quantity a task to think about how crowded tarpaulins are ?
is given as shown in figure 2 Actual lessons will often start with an arithmetical activity
designed to let the children experience for themselves how crowded a place is In the case of Figure 2 since the number of tarpaulins is the same in both a and b children soon realize that
a is more crowded On the other hand when comparing b and c since the number of people is same it is evident that C is more crowded As a result the main objective of this lesson is the comparison between a and c and the focus becomes the problem of thinking of a method for comparing crowdedness when both tarpaulins and people differ in number