Unit 7
Data and Percentage
About this unit
Read and interpret tables, bar charts, pie charts, and surveys — then use the data to calculate percentages, make comparisons, and answer multi-step numerical questions. This unit covers everything from reading a simple graph to computing layered percentage breakdowns.
What types of questions will you face?
- 1Calculate the percentage of a group from a bar or pie chart
- 2Compute the overall percentage when different-sized groups have different rates
- 3Find the "most improved" student or item using a ranked comparison table
- 4Determine a minimum score needed to guarantee winning a competition given partial results
- 5Read multi-column survey data and perform arithmetic across groups to find totals or percentages
Skills you will build
- Reading and extracting data accurately from tables, bar charts, and sector graphs
- Calculating percentages from fractions and whole numbers
- Combining percentages from groups of different sizes (weighted averages)
- Applying arithmetic and comparison logic to ranked data
- Performing multi-step calculations without a calculator
By the end of this unit, you will be able to
- Accurately extract numerical data from any graph or table format
- Calculate percentages across different group sizes without confusion
- Solve "minimum score needed" type competition problems by working backwards
- Interpret data to draw valid conclusions and avoid misleading readings
Difficulty profile
Easy difficulty (avg 2.46). Most questions are straightforward percentage and reading problems. The harder questions involve combining data from multiple-sized groups.
Exam tip: Data and Percentage
For percentage of a combined group: always multiply the proportion by the GROUP SIZE before adding. Never average percentages directly — a group of 1,000 at 50% contributes far more than a group of 10 at 90%.
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