**GRE Data Interpretation: Multi-Step Tables, Charts, and Graphs – Complete Study Guide**

GRE Data Interpretation: Multi-Step Tables, Charts, and Graphs – Complete Study Guide

(For Serious 320+ Scorers)

What This Is

Data Interpretation (DI) questions test your ability to extract, compare, and manipulate data from tables, bar charts, line graphs, and pie charts—often in multi-step problems requiring arithmetic, percentages, ratios, or unit conversions. These questions appear in every GRE Quant section (2–4 per section) and are high-value: they reward careful reading and methodical calculation, not advanced math. A single DI set can net you 3–4 raw points if you avoid careless errors.

Real-GRE Example:
A bar chart shows annual revenue (in millions) for Companies A, B, and C from 2018–2022. The question asks: “In 2021, what percent of the combined revenue of Companies A and B was Company C’s revenue?” → You’ll need to: 1. Read the 2021 values for A, B, and C.
2. Sum A + B.
3. Divide C by (A + B).
4. Convert to a percentage.

Key Concepts & Techniques

1. Scan First, Calculate Later
2. What it is: Read the title, axes, legends, and units before diving into calculations.

3. When to use: Every DI question. Skipping this step leads to misreading units (e.g., thousands vs. millions) or misinterpreting trends.

4. Approximate to Save Time

5. What it is: Round numbers to the nearest 10 or 100 to simplify arithmetic (e.g., 47% ≈ 50%, 198 ≈ 200).

6. When to use: When answer choices are spread out (e.g., 25% vs. 50% vs. 75%). Avoid approximating if choices are close (e.g., 47% vs. 49%).

7. Multi-Step Roadmap

8. What it is: Break the question into discrete steps (e.g., Step 1: Find X; Step 2: Calculate Y; Step 3: Compare X and Y).

9. When to use: For questions with phrases like “what percent greater,” “ratio of,” or “combined total.”

10. Unit Awareness

11. What it is: Note whether data is in thousands, millions, or percentages and convert if needed.

12. When to use: When the question asks for a different unit than the chart (e.g., chart shows millions, question asks for thousands).

13. Trend vs. Value Questions

14. What it is:
    • Trend questions ask about changes over time (e.g., “Which company’s revenue grew the fastest?”).
    • Value questions ask for specific numbers (e.g., “What was Company A’s revenue in 2020?”).

15. When to use:

    
    
    • For trends, focus on slopes of lines or bar heights.
    • For values, read exact data points.

16. Pie Chart Angles

17. What it is: A pie chart’s total = 360°. Each category’s angle = (category % × 3.6).

18. When to use: When the question asks for percentages or proportions but only provides angles.

19. Double-Bar/Line Comparisons

20. What it is: Compare two data series (e.g., revenue vs. profit) by subtracting or dividing.
21. When to use: For questions like “How much more did X exceed Y in 2021?”

Step-by-Step Strategy

Follow this process for every DI question:

1. Read the Question First
2. Underline what’s being asked (e.g., “percent increase,” “ratio,” “total”).

3. Circle key years/categories (e.g., “2021,” “Company B”).

4. Extract the Relevant Data

5. Pull only the numbers needed from the chart/table.

6. Write them down with units (e.g., “A = 45M,” “B = 30M”).

7. Plan the Calculation

8. Write the formula you’ll use (e.g., % change = (New – Old)/Old × 100).

9. Break it into small steps (e.g., Step 1: Sum A + B; Step 2: Divide C by sum).

10. Approximate (If Safe)

11. Round numbers to simplify (e.g., 47% → 50%, 198 → 200).

12. Check if answer choices allow approximation.

13. Execute the Math

14. Do one step at a time (e.g., first sum, then divide).

15. Double-check units (e.g., millions vs. thousands).

16. Match to Answer Choices

17. Compare your result to the choices.
18. If no match, recheck calculations or re-read the question.

Fully Worked GRE-Style Example

Question:
The table below shows the number of employees (in thousands) at four companies from 2019–2022.

In 2022, what percent of the total employees at Companies A and B were employed at Company C?

Solution Using the Strategy:

1. Read the Question First

2. Asks for percent of (A + B) that is C in 2022.

3. Extract the Relevant Data

4. A (2022) = 20K
5. B (2022) = 15K

6. C (2022) = 9K

7. Plan the Calculation

8. Step 1: Sum A + B = 20 + 15 = 35K
9. Step 2: Divide C by (A + B) = 9 / 35

10. Step 3: Convert to percentage = (9 / 35) × 100

11. Approximate (If Safe)

12. 9 / 35 ≈ 10 / 35 = 2/7 ≈ 28.6%

13. Answer choices (not shown here) would likely include ~25% and ~30%, so approximation is safe.

14. Execute the Math

15. 9 ÷ 35 = 0.257 → 25.7%

16. Closest to 25.7%, but since we approximated, we’d pick the ~26% choice.

17. Match to Answer Choices

18. If choices were:
    A) 20%
    B) 25%
    C) 30%
    D) 35%
19. Correct answer: B) 25%

Common Mistakes

1. Mistake: Misreading Units
2. Why it happens: Skipping the chart’s units (e.g., thousands vs. millions).

3. Correct approach: Circle the units in the chart and question. Convert if needed.

4. Mistake: Calculating the Wrong Year/Category

5. Why it happens: Not underlining the specific year/category in the question.

6. Correct approach: Highlight the year/category (e.g., “2021,” “Company D”) before extracting data.

7. Mistake: Overcomplicating Multi-Step Problems

8. Why it happens: Trying to do all steps in your head.

9. Correct approach: Write down each step (e.g., Step 1: Sum; Step 2: Divide).

10. Mistake: Ignoring “Approximate” Cues

11. Why it happens: Doing exact math when answer choices are spread out.

12. Correct approach: Round numbers if choices differ by >5%.

13. Mistake: Forgetting to Convert Units

14. Why it happens: Assuming the chart’s units match the question’s.
15. Correct approach: Check units (e.g., chart = millions, question = thousands → multiply by 1,000).

GRE Traps & Timing

1. Trap: Hidden Unit Conversions
2. How to spot: The chart says “(in thousands)” but the question asks for “actual numbers.”

3. How to avoid: Convert first (e.g., 12K = 12,000).

4. Trap: “Combined” vs. “Individual” Questions

5. How to spot: The question asks for “combined revenue of A and B” but the chart shows individual values.

6. How to avoid: Sum first, then calculate.

7. Trap: Percent Change vs. Percent Of

8. How to spot:
   • Percent change: “Increased by what percent?”
   • Percent of: “What percent of X is Y?”

9. How to avoid: Write the formula before calculating.

10. Timing Budget

11. Easy DI question: 60–75 seconds.
12. Hard DI question (multi-step): 90–120 seconds.
13. If stuck: Flag and return later—don’t waste 3+ minutes.

Quick Practice

Question:
A pie chart shows the distribution of a $1.2M budget: 90° for Salaries, 120° for Operations, 60° for Marketing, and the rest for Miscellaneous. What is the dollar amount allocated to Marketing?

Answer:
- Total angle = 360°.
- Marketing angle = 60° → 60/360 = 1/6 of budget.
- 1/6 × $1.2M = $200,000.

Last-Minute Cram Sheet

1. Always read the question first—underline what’s asked.
2. Scan units (thousands? millions?) before calculating.
3. Approximate if answer choices are spread out.
4. Break multi-step into parts (e.g., sum → divide → convert).
5. Pie chart angle = % × 3.6 (e.g., 90° = 25%).
6. Percent change = (New – Old)/Old × 100.
7. Percent of = (Part/Whole) × 100.
8. Double-check years/categories—ETS loves to swap them.
9. If stuck, flag and move on—DI questions can be time-sinks.
10. ⚠️ Trap: “Combined” ≠ “individual”—sum first if needed.