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.

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:

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:

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 |

1 |
2 |
3 |
4 |
5 |
||

6 |
7 |
8 |
9 |
10 |
11 |
12 |

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: