Data handling: count, draw and read
Collect data with a question, and work with graphs, mean, median, mode, range and pie charts. Read one step, play with it, then tap “I understand this”.
Start with a question
Data is information we collect to answer a question. It always follows the same cycle:
- Ask a question: “Which sport does our class like most?”
- Collect the answers, for example with a questionnaire.
- Organise it in a table with tally marks.
- Show it in a graph.
- Read and explain what the graph tells you.
Count with tally marks
Tally marks help you count quickly without mistakes. Draw one line for every answer. The fifth line goes across the first four: that makes a bundle of 5.
The survey
Tap each child’s answer once. The table counts along.
Bundles of 5 are quick to count: 5, 10, 15 … It is much faster, and you make fewer mistakes than counting 17 loose lines one by one.
Draw a graph
A bar graph shows each group as a bar. A pictograph uses pictures, and the key tells you how much one picture is worth.
The graph builder
Change the numbers and switch between the two graphs.
Always look at the scale or the key before you read. If one picture is 2 children, then 4 pictures are 8 children, not 4.
A table full of numbers is hard to understand at a glance. In a graph you see straight away which bar is the tallest and how big the difference is.
Read the graph
What does the graph say?
Read the graph and choose the answer.
Correct: 0Mean, median, mode and range
Mean: add up and divide. Median: the middle one. Mode: the most common. Range: biggest − smallest.
The data cards
Choose a measure and tap “New data”.
Sort the numbers first from small to big. The middle number in the unsorted list is not the median.
The median is the middle value: half the data is smaller and half is bigger. That only works when the numbers are in order. In a jumbled list the middle number is just there by chance.
Each tells you something different. If one millionaire moves to a small town, the mean income jumps, but the median still shows what an ordinary person there earns.
Pie charts
A pie chart shows each group as a part of the whole circle. The whole circle is all the children who were asked. We write the parts as percentages: the whole circle is 100%.
The pie chart
Change how many children were asked and choose a sport.
The whole circle is all the people together. Each slice shows what part of the whole that group is, so you see straight away which group has the biggest share.
Check yourself
- Data cycle: ask, collect, organise, show, read.
- Tally marks in bundles of 5: the fifth line goes across.
- Always read the scale or the key first.
- Mode: the value that comes up most often.
- Median: sort first, then the middle value.
- Mean: add everything and divide by how many there are. Range: biggest − smallest.
- Pie chart: the whole circle is everyone; each slice is a percentage of it.
Write these points in your maths book. Read them again the night before the test.
Quick questions
Tap an answer. If you get one wrong, read why and go back to that step. You get new questions every time.
You ticked all 6 steps! Now you are ready for the quiz.- Practice sheet for this classQuestions + memo · 2 A4 pagesPractice sheet
- Data handling7 pages · PDFPaperMemo
Ready for more? The Grade 7 data handling quiz gives you new questions every time.
- One step a day is enough. Ten calm minutes work better than an hour the night before the test.
- Do a survey together at home: “Which colour cars drive past in 10 minutes?” Count with tally marks and then draw a bar graph.
- Ask your child to tell you the rule in their own words. If they can explain it, they understand it.
- The ticks (“I understand this”) are saved on this device only. We never ask for names or emails.
Follows CAPS for Grade 7 Maths. Always check your teacher’s notes and textbook too.