Section 5 - Charts & Graphs

Posters, adverts and the media make use of graphs to illustrate mathematical information. This data can be presented in many forms, and it is important that you are introduced to a variety of representations while you are at school.

Different types of graph

a. Pictograph
Ask your friends, ‘What is your favourite colour?’ Represent each friend with a face coloured with their favourite colour:

b. Block graph
Each friend can be represented in the display by a square:

c. Bar graph
Instead of each friend being displayed by an individual face or square, the whole group can be shown by a bar. If this graph is drawn on squared paper it is easy to find out how many squares have been joined to make the bar:

d. Spike graphs
Now change the bars to lines:

e. Point graphs
Now you are going to record only a point, which is like the tip of the spike, instead of a line. Points are positioned according to their relationship to each of the two axes (vertical and horizontal):

f. Pie Chart
Have a look at this Pie Chart. The size of the sectors are used like the bars in a bar chart. Each slice is a part or fraction of the whole circle:

Making your own surveys

a. Survey of foot sizes
Now try making a survey of your own. Firstly you have t collect your information. Go round your family and friends to measure their feet without their shoes on. Record each foot size and tally each measurement as shown below:

Make a Tally chart: (size of foot in mm)

210-219 220-229 230-239 240-249 250-259 260-269 270-279 280-289
/ /// //// ////// ///////// /////// //// ////
Number of relatives and friends surveyed = 38 people.


b. Make your own surveys
Make a survey of your own. Collect information, and then make a tally chart and a graph. Here are some suggestions for your survey:

c. Road census
An investigation on the traffic that passes your house, or nearby, can be interesting. Your survey will include: Lorries, vans, cars, motorcycles, bicycles and pedestrians. It is best to do your census during a set period of time, say from 8.30 to 9.30 a.m. Make sure that you use a good ‘tally system’. Usually the counting is done in fives. On the 5th count a mark across the first four is made:

Your road census can be developed into a block graph:

This can then be developed into a bar chart. The quantity or in this case the number of vehicles is not so clearly represented on the bar chart. There is now a need for a scale to show the quantities:

Other activities with graphs

a. Weather chart
Make a simple weather chart. Use these cards to show the different elements of weather:

Each symbol represents one day. At the end of a month one can see what type of weather was more frequent. A weather chart is made. For each school day in the month, a card is placed on the chart:

Weather for August
Monday Tuesday Wednesday Thursday Friday Saturday Sunday

b. Investigations and graphs
You can make some investigations at your school or amongst your friends:


c. Ready reckoner
Have a look at the next interesting graph. It shows the products for the 2x, 5x, 7x and 9 times multiplication tables. Check it to see if it works:

d. Pie charts
You will learn more about Pie Charts when you get a bit older, but here is why they are called Pie Charts as they look like a pie:

left up right