why should we put tally marks is it compalsary?????????????
Here is the answer to your question.
Tally marks are used to maintain and count the number of observations.
We arrange any data in tabular form using tally marks to obtain particular information in very little time.
In order to understand the concept of tally marks, let us arrange the following data using tally marks. The given data represents the number of blood donors of different blood groups in a blood donation camp.