Interpret charts, maps and data tables

Charts, maps and data tables present information in a visual form. Instead of reading long paragraphs, you scan rows, columns, axes and keys to find the exact values you need. Practicing these skills allows you to answer data questions quickly and accurately.

Reading bar charts and line graphs

A bar chart uses rectangular bars of different heights to compare values across categories. The horizontal axis (x-axis) shows the categories — months, countries, products — and the vertical axis (y-axis) shows the measured values. To read a value, trace a straight line from the top of a bar across to the y-axis. A line graph works the same way, but dots connected by lines show change over time rather than separate bars.

• Read the chart title first so you know what is being measured.
• Check the y-axis label and scale — each division may represent 10, 100, or 1,000 units.
• Identify which bar is tallest (highest value) and which is shortest (lowest value).
• Describe trends: "Values increased from January to March, then fell in April."

Reading pie charts

A pie chart divides a circle into slices. Each slice represents a proportion of the whole — usually shown as a percentage. The largest slice represents the category with the highest share. To answer questions, compare slice sizes and read the percentage labels.

Reading maps with a key or legend

A map key (also called a legend) explains what each color, symbol or pattern on the map stands for. To answer a map question, first read the key to understand the symbols, then locate the relevant area or feature on the map itself.

• Read the map title to understand what type of information is shown.
• Study the key before looking at the map — know what each symbol means.
• Use compass directions (North, South, East, West) to describe location.
• Compare regions by their colors or symbols to answer "which area has most/least?" questions.

Reading data tables

A data table organizes information into rows and columns. Column headings appear at the top; row labels appear on the left. To find a specific value, locate the correct row and trace across to the correct column — or trace down from the column heading to the correct row.

• Read both the column heading and the row label carefully before reading the cell value.
• Check any units shown in the heading (kg, km, %, etc.).
• Scan a whole column to find the highest or lowest value.
• Compare two or more rows to describe a difference or trend.