Tally marks
Tally marks are defined in the unary numeral system. It is a form of numeral used for counting. The general way of writing tally marks is as a group or set of five lines. The first four lines are drawn vertically and each of the fifth line runs diagonally over the previous four vertical lines, i.e. from the top of the first line to the bottom of the fourth line
Counting Tally Marks
Tally marks are the fastest way of keeping track of numbers in groups of five. See the figure below to understand the logic
We can see here;
One is expressed by ‘I’ tally mark.
Two is represented by ‘II’ tally marks.
Three is represented by ‘III’ tally marks.
our is denoted by ‘IIII’ tally marks.
Five is not denoted by ‘IIIII’ tally marks in the graphs. For the number 5, draw four vertical lines (IIII) with a diagonal (\) line through it
Example 1:
Let’s consider the marks of 25 students in standard IX in a particular school. The scores are as follows: 41, 53, 64, 31, 53, 33, 70, 61, 74, 32, 53, 56, 56, 64, 56, 88, 28, 70, 56, 64, 74, 53, 53, 61, 31.
The maximum mark allotted to the paper is 100. Draw a tally chart for the above data.
Solution: Rearranged data in ascending order
Example 2
Consider a garden with lots of flowers. Mary has different types of flower pots which are given in the table below
Using this table, answer the below questions:
(i) How many Daisy flower pots are there?
(ii) Which two flowers have the same number of pots?
Solution:
Using the given tally mark table, we can easily get the required information without actually going through the observations
(i) It can be seen that there are two tally marks in front of the Daisy row. So the number of Daisy flower pots is 2
(ii) It can be seen that in front of Lily and Jasmine, the number of tally marks is 4. So both Lily and Jasmine have the same number of pots