Data Interpretation questions on the GRE present a shared data display — a table, bar chart, line graph, or pie chart — followed by two to five questions that require you to extract values and perform calculations. The arithmetic subset of these questions asks you to compute percentages, ratios, averages, and unit conversions directly from the displayed data. These questions rarely involve complex formulas, but they punish careless reading and sloppy computation. Below you will learn the five arithmetic patterns that appear, work through two interactive examples step by step, and then practice with six guided questions drawn from realistic DI data sets.
What Are DI Arithmetic Questions?
On the GRE Quantitative Reasoning measure, Data Interpretation questions come in sets. Each set opens with one or more data displays — a table of sales figures, a pair of pie charts, a line graph tracking production over time — and then asks two to five questions about that data. When those questions require you to perform arithmetic operations like computing a percentage of a total, finding the percent change between two years, calculating an average, or converting between units, they fall into the DI Arithmetic category.
The arithmetic itself is secondary-school level: multiplication, division, fractions, and percentages. What makes these questions challenging is the data extraction step. You must read the correct row and column from a table, identify the right bar on a chart, or combine values from two separate displays. The GRE test makers design wrong answers to match the result you would get if you read the wrong cell, used the wrong base for a percent calculation, or forgot to convert units. Precision in reading the data display is just as important as precision in the arithmetic.
Frequency note: Arithmetic is one of the two most common skill domains tested in DI sets, alongside Data Analysis. Nearly every DI set on the GRE includes at least one question that is primarily arithmetic in nature. Expect to see multiple DI arithmetic questions on test day, spanning a range from straightforward percent-of-total calculations to multi-step unit conversions.
5 Patterns You'll See
Nearly every DI arithmetic question falls into one of five calculation patterns. Recognizing the pattern from the question stem tells you exactly what formula to apply and which values to pull from the data display.
1
Percent of a Total
Multiply a percentage by a total to find a part, or divide a part by a total and multiply by 100 to find a percentage. Common stems: 'What percent of total sales were from Department X?' or 'What were the sales of X, given that X was 16% of total?'
2
Percent Change
Apply the formula OldNew−Old×100. Stems often ask "What was the percent change from Year A to Year B?" or "By approximately what percent did production increase?" The base is always the earlier or original value.
3
Ratio and Proportion
Divide one quantity by another to form a ratio, or set up a part-to-whole relationship. Common stems: 'What is the ratio of students to faculty?' or 'What fraction of all employees are in department Y?'
4
Average (Arithmetic Mean)
Sum a set of values and divide by the count. Stems include 'What was the average annual production for the years 2013 through 2017?' Watch for questions that ask how much greater the average is than a single value.
5
Unit Conversion
Convert between units using a given factor, such as tonnes to bushels or billions to millions. The conversion factor is typically stated in the question or in a note below the data display. These questions often combine with percent-of-total as a preceding step.
How to Solve DI Arithmetic Step by Step
These five strategies apply across all five arithmetic patterns. Internalizing them will help you avoid the careless errors that the GRE is specifically designed to exploit.
DI arithmetic questions often require two or three sequential steps. Write down each intermediate result on your scratch paper before moving to the next step. If you try to hold intermediate values in your head, you risk transposing digits or losing track of which number belongs to which step. For example, when computing a percent of a total that then feeds into a unit conversion, record the percent result before dividing by the conversion factor.
Many DI questions include the word "approximately" or "closest to." This is a deliberate signal from the test makers that the answer choices are spread far enough apart for estimation to work. If the choices are 40%, 60%, 70%, 120%, and 140%, you do not need to compute to the decimal place. Round inputs to convenient numbers, perform the calculation mentally, and pick the closest choice. This can save 30 to 60 seconds per question.
When computing ratios or percentages from table values, cancel common factors early rather than multiplying large numbers and dividing at the end. For example, if you need 275 / 34, recognize that 275 is close to 280 and 34 is close to 35, so the answer is near 280 / 35 = 8. On the GRE, clean estimation beats brute-force long division every time.
For "percent of" questions, the denominator is the total or the reference group. For "percent change" questions, the denominator is always the old value. The single most common arithmetic error on DI questions is dividing by the wrong number. Before you compute, circle the base value on your scratch paper and label it "base" or "denominator" so there is no ambiguity.
Percent change = OldNew−Old×100. Never divide by the new value. This formula applies whether the change is an increase or a decrease — if the result is negative, the change is a decrease. Writing the formula out every time, rather than relying on intuition, prevents the most frequent percent change error on the GRE.
Pro tip: When answer choices include a value that matches an intermediate step of your calculation, it is almost certainly a trap. The GRE deliberately places partial results among the choices to catch test-takers who stop one step early. Always verify that you have completed every step the question requires before selecting your answer.
Worked Example: Ratio from Combined Data Displays
Work through each step below. You must answer each mini-challenge correctly to unlock the next step. If you get stuck, a second wrong attempt will reveal the answer so you can keep going.
Interactive Walkthrough0/5 steps
Student-to-Faculty Ratio from Pie Charts
Two pie charts show the distribution of faculty at College X. There are 200 adjunct faculty and 250 non-adjunct faculty. Engineering accounts for 2% of adjunct and 12% of non-adjunct. There are 275 students in the field of engineering.
Approximately what is the ratio of the number of students in engineering to the number of faculty in engineering?
1
Step 1: Compute adjunct engineering faculty
Engineering is 2% of 200 adjunct faculty. How many adjunct faculty are in engineering?
2
Step 2: Compute non-adjunct engineering faculty
3
Step 3: Find total engineering faculty
4
Step 4: Set up the ratio
5
Step 5: Verify by estimation
Worked Example: Percent Change from a Table
This example walks through a percent change calculation where the answer choices are deceptively close together. Precision matters here — estimation alone will not distinguish a 0.8% increase from a 1.0% decrease.
Interactive Walkthrough0/6 steps
Computing a Small Percent Change
A table titled "Selected Sales Data for Store X" shows departmental sales in billions of dollars for 2014, 2015, and 2016. The Paint department had sales of $12.50 billion in 2014 and $12.60 billion in 2016.
Which of the following is closest to the percent change in annual sales of the Paint department from 2014 to 2016?
1
Step 1: Identify the Old and New values
Which value is the Old value (the base for percent change)?
2
Step 2: Compute the difference (New - Old)
3
Step 3: Divide by the Old value
4
Step 4: Convert to a percentage
5
Step 5: Is this an increase or a decrease?
6
Step 6: Eliminate the trap answers
Practice Questions
Now apply what you have learned. Each question includes a step-by-step solution walkthrough — after you submit your answer, click through the solution one step at a time to compare against your own work. The questions are grouped by their shared data display, just as they would appear on the actual GRE.
Container Shipping Ports — Throughput and Revenue Data
Table 1: Container Throughput and Revenue Data for Six Major Ports (2023)
Port
Throughput (M TEUs)
Handling Fee ($/TEU)
Warehouse Rate ($/TEU/day)
Shanghai
47.3
$192
$8.40
Singapore
38.6
$225
$9.60
Busan
22.8
$205
$7.80
Rotterdam
13.4
$290
$12.50
Los Angeles
9.2
$345
$15.20
Durban
4.7
$162
$6.40
Table 2: Year-over-Year Percent Change in Container Throughput
Port
2019-2020
2020-2021
2021-2022
2022-2023
Shanghai
-1.8%
+8.1%
-5.2%
+4.6%
Singapore
-0.9%
+1.6%
+7.2%
+3.4%
Busan
-4.2%
+8.5%
+6.1%
+3.8%
Rotterdam
-3.1%
+6.4%
-2.8%
+5.7%
Los Angeles
-7.5%
+13.2%
-10.4%
+2.1%
Durban
-6.0%
+4.8%
+3.2%
+1.5%
Table 3: Handling Fee per TEU (in US dollars)
Port
2022 Fee
2023 Fee
Shanghai
$185
$192
Singapore
$210
$225
Busan
$198
$205
Rotterdam
$275
$290
Los Angeles
$320
$345
Durban
$155
$162
Note: Average dwell time in port warehouses was 3.2 days per TEU across all ports in 2023.
Question 1 — Revenue Difference (Multiplication and Subtraction)
The total handling revenue (throughput multiplied by handling fee per TEU) generated by Singapore in 2023 was approximately how many million dollars greater than the total handling revenue generated by Busan in 2023?
In 2023, the total warehouse charges (throughput multiplied by warehouse rate multiplied by average dwell time of 3.2 days) collected by the Port of Singapore exceeded those collected by the Port of Rotterdam by approximately how many million dollars?
National Consumer Expenditure Survey — Household Spending Data
Table 1: Average Annual Household Expenditure by Category and Income Quintile (2023)
Category
Q1 (Lowest 20%)
Q2
Q3
Q4
Q5 (Highest 20%)
Housing
$8,400
$12,600
$18,200
$26,400
$42,800
Food
$4,800
$6,200
$8,400
$11,000
$16,600
Transportation
$3,200
$5,600
$8,800
$13,200
$19,400
Healthcare
$3,600
$4,400
$5,600
$7,200
$9,800
Insurance & Pensions
$1,400
$3,800
$6,400
$10,800
$18,600
Entertainment
$1,200
$2,400
$3,800
$5,800
$11,200
Education
$600
$1,000
$2,200
$4,800
$10,400
All Other
$2,800
$4,000
$6,600
$8,800
$15,200
Total
$26,000
$40,000
$60,000
$88,000
$144,000
Table 2: Percent Change in Average Annual Expenditure from 2022 to 2023
Category
Q1
Q2
Q3
Q4
Q5
Housing
+5.0%
+4.1%
+3.5%
+2.8%
+2.2%
Food
+8.2%
+6.9%
+5.5%
+4.6%
+3.8%
Transportation
-2.4%
+1.8%
+3.5%
+4.8%
+6.0%
Healthcare
+6.5%
+5.8%
+5.0%
+4.2%
+3.6%
Insurance & Pensions
+3.7%
+4.1%
+3.2%
+2.5%
+1.9%
Entertainment
-4.8%
+2.0%
+3.8%
+4.5%
+5.2%
Education
+1.7%
+2.5%
+3.1%
+3.5%
+3.0%
All Other
+2.9%
+3.3%
+2.8%
+2.2%
+1.8%
Note: Each quintile represents approximately 26.4 million households in 2023.
The average annual expenditure on Food for first-quintile households in 2022 was closest to which of the following?
Question 6 — Percent of Total (Conditional Selection)
What percent of the total 2023 household expenditure for fourth-quintile households was spent on categories that experienced a percent increase of more than 4 percent from 2022 to 2023?
Common Traps
Trap 1 — Percent vs. Percentage Points. A change from 25% to 30% is a 5-percentage-point increase, but it is a 20% increase (because 5/25=0.20). GRE Data Interpretation questions frequently test whether you know the difference. If the question asks for the "percent increase," you must divide the change by the original rate. If it asks for the change "in percentage points," you simply subtract. Confusing these two concepts shifts your answer by an order of magnitude.
Trap 2 — "Greater Than" vs. "Of" in percent questions. "A is what percent of B?" yields A/B×100. "A is what percent greater than B?" yields (A−B)/B×100. These produce very different answers. For example, if exports are $12 billion and imports are $5 billion: exports are 240% of imports (12/5=2.40), but exports are 140% greater than imports ((12−5)/5=1.40). On the GRE, both 240% and 140% will typically appear among the answer choices, and the question stem will use one phrasing or the other. Read the stem word for word.
Trap 3 — Using the wrong base for percent change. Percent change = OldNew−Old×100. The denominator must always be the Old value. The most common arithmetic error on DI percent change questions is dividing by the New value instead. This error is especially tempting when the question presents the new value first or when you are computing a percent decrease (where the Old value is larger). Write "OLD" next to the denominator on your scratch paper every time to prevent this mistake.
Recognition / When to Apply
Not every DI question that involves numbers is arithmetic. Some require algebra (setting up equations from data), and others are pure data analysis (reading trends, comparing distributions). Use this table to quickly identify when a DI question calls for arithmetic skills specifically.
Question Stem Pattern
Arithmetic Type
Key Operation
What percent of total X was Y?
Percent of total
Divide part by whole, multiply by 100
What was the percent change from Year A to Year B?
Percent change
OldNew−Old×100
What is the ratio of A to B?
Ratio
Divide A by B and simplify
What was the average value over the period?
Arithmetic mean
Sum all values, divide by count
How many bushels is N million tonnes?
Unit conversion
Multiply or divide by the conversion factor depending on the direction of conversion
Year A value as percent of Year B value?
Reverse percent
Divide Year A by Year B, multiply by 100
If each group has N members, what is the total?
Scaling
Multiply per-unit value by count
The distinguishing feature of DI arithmetic is that all values are available directly in the data display — you do not need to set up an equation, introduce a variable, or reason about an unknown. If the question requires you to solve for something not shown in the display, it has crossed into algebra territory. If it asks you to identify a trend or describe a distribution without computing a specific number, it is data analysis. DI arithmetic sits in the middle: extract specific values, then compute.
Study Checklist
DI Arithmetic Mastery Checklist0/10 complete
Frequently Asked Questions
How often do arithmetic-based Data Interpretation questions appear on the GRE?
Arithmetic is one of the two most common skill domains tested in GRE Data Interpretation sets, alongside Data Analysis. Nearly every DI set includes at least one question that is primarily arithmetic in nature, so you should expect multiple DI arithmetic questions on test day. Their difficulty ranges from easy single-step percent calculations to harder multi-step problems that chain together percent, ratio, and unit conversion operations.
What is the difference between DI arithmetic and standalone arithmetic on the GRE?
In a standalone arithmetic question, all the values you need are stated directly in the problem. In a DI arithmetic question, you must first extract the correct values from a shared data display — a table, graph, or chart — and then perform the computation. The arithmetic operations themselves are the same (percentages, ratios, averages), but the added step of reading data from a visual display introduces a new category of errors: reading the wrong row, confusing columns, or misinterpreting the units on a graph axis.
What types of calculations appear most often in DI arithmetic questions?
The five most common calculation types are percent of a total, percent change between two periods, ratios and proportions, arithmetic mean (average), and unit conversion. Mastering these five operations covers the vast majority of DI arithmetic questions on the GRE. Percent-of-total and percent-change questions are by far the most frequent, accounting for roughly two-thirds of all DI arithmetic items in official practice materials.
How do I avoid wrong-base errors on percent change questions?
Always use the formula: Percent Change = OldNew−Old×100. The denominator must be the Old value, not the new value. Before plugging in numbers, write the formula on your scratch paper and label which number is Old and which is New. This simple habit eliminates the single most common arithmetic error on DI percent change questions. Also be cautious when reversing a percent change: if a value increased by r% to become y, the original value is y/(1+r/100), not y×(1−r/100).
Should I estimate or calculate exactly on DI arithmetic questions?
It depends on the answer choices. If they are spread far apart — such as 40%, 60%, 70%, 120%, and 140% — aggressive estimation saves time and is usually sufficient. If they are tightly clustered — such as a 0.8% increase and a 1.0% decrease — you need precise calculation. Many GRE DI questions include the word "approximately" or "closest to," which is a deliberate signal that estimation is both allowed and encouraged. Look at the answer choices before you start computing to decide how much precision you need.