Builds on
Number systemReading, comparing and rounding numbers comes first when you sort data and round a mean.
Data handling
What is a typical value — and how can one number summarise a whole class?
Collecting and organising data, tally marks and frequency tables, bar graphs, and summarising data with mean, median, mode and range.
5 depths≈ 240 min of reading80 practice questions
The ladder
Choose how deep to go
Every depth is open. Start where it feels interesting — you can always move back.
- Discoverabout 35 minCounting what matters: meeting dataAsk a question, collect answers, and turn a jumble of raw data into tally marks, tables, pictographs and bar graphs. Then meet four friendly numbers that sum up a whole group: the fair share (mean), the middle (median), the most common (mode) and the spread (range).Owner-accepted · not line-by-line reviewed
- Understandabout 45 minOrganise, picture, summarise: how the methods workTell categorical from numerical data, build self-checking frequency tables, choose a key or scale for pictographs and bar graphs, and use exact methods for mean, median (odd and even counts), mode (two modes or none) and range, even from a frequency table.Owner-accepted · not line-by-line reviewed
- Investigateabout 45 minWhat happens if…? Experiments with averagesTreat averages like a science experiment. Predict what adding a value, an outlier, or a change to every value does to the mean, median, mode and range, then test it in the labs. Build data sets to order, hunt missing values and compare real Indian data.Owner-accepted · not line-by-line reviewed
- Go deeperabout 55 minWhy averages work, and which one to trustProve the mean is a balance point and how it reacts to shifts and scaling. Combine groups correctly, handle grouped data with class intervals, read double bar graphs, and choose between mean, median and mode with outliers, cricket averages and average speeds. Plus a history of statistics in India.Owner-accepted · not line-by-line reviewed
- Extendabout 60 minData in the wild: pie charts, tricks, chance and projectsTurn data into pie charts with angles, spot graphs that mislead, describe chance from impossible to certain, and run real projects on electricity bills, the census and monsoon rain. Think about privacy and fairness in data, meet careers built on data, and try olympiad-style puzzles.Owner-accepted · not line-by-line reviewed
Practise and apply
Question bank · 80 questions
9 sections from Foundation to Challenge, each with hints and a worked solution — or play a 10-question round for points and stars.
Foundation 18Core 30Stretch 22Challenge 10
The web
Connected ideas
Follow a connection when you’re curious — some lead into completely different areas.
Data handling
Used inanother area
ElectricityA family's monthly electricity use varies; the mean, median and range of a year of bills show what is typical.
Usesanother area
How government works in IndiaA census, an election result and a budget are all data: counted, summarised and argued over.
Usesanother area
TidesA tide table is a data set: measure the water twice a day for years, and the pattern lets you predict it.
Usesanother area
Anatomy of the human bodyHeart rate, height and lung capacity across a class are real data to collect, average and compare.
Usesanother area
Body systems and how they connectPulse and breathing rate before and after exercise are real class data to average, compare and graph.
Words to know
68 words are explained in these lessons
datasurveyquestionnaireobservationraw datatally markfrequencyfrequency tablepictographkeybar graphscale+56 more