There are two varieties of SAT questions on charts and graphs. The first type asks you to look at data organized in a chart or graph and interpret it. The second type asks you to perform some type of operation on data found in a chart or graph, such as calculating a mean or a percent.

Reading charts and graphs questions are pretty simple: the question will show you a chart or graph and then ask you about the data presented.

It may be that you look at this question and realize that you don’t know what the term “net income” means. That doesn’t matter. The graph tells you that the bars represent net income, so all you have to do is interpret the bars to figure out between which months the net income differed most. This is a key fact about SAT charts: you don’t have to completely understand the terms that describe the data in the chart, you just have to be able to figure out how the data is related. In the case of this chart describing net income, it is only important that you see that the net income changes from month to month.

To figure out the two months between which Joe’s net income changed most, you need to determine which two bars on the graph represent the two numbers that are most different in size. For this graph, the two biggest differences in terms of net income per month are obviously between April and May, and between February and March. The net income in April was $20 and the net income in May was $50, making the April-May difference $30. The net income in February was $30 and the net income in March was –$10, so the February-March difference was $40. The answer, therefore, is February to March. This question throws a tiny trick at you by including negative numbers as net income. If you don’t realize that March is negative, then you might choose the April–May difference. When dealing with graphs and charts, be sure to pay attention to negative and positive values.

This second type of charts and graphs question asks you to do more than just interpret a graph or chart. You must also use the data and perform some operation on it in order to get the right answer. For instance, you may be asked to figure out the mean of the data shown in a graph. You might also be asked to look at a bar graph like the one shown previously and then to calculate the percentage change in net income between two of the months. Here’s a question involving that same graph from before:

To answer this question, you first have to make sure you understand what it is asking. First, the question mentions percent increase. This means that the question is asking you to find out how much the net income increased between April and May and then to compare that increase to the original net income in April. The difference between the net incomes from April to May is the increase in income. The percent increase of net income can only be found if you look at that increase in relation to the original income. (You should know what percent increase means from our discussion of percents starting on .)

Once you’ve figured out what the question is asking for, working out the math is easy. The difference in net income between April and May is:

Now, to calculate the percent increase, you have to divide the change in net income by the original income in April:

Here’s the final trick in the question. The answer is not 1.5% change. Remember, to get percents, you must multiply by a hundred. The answer is therefore But you can be sure that in this sort of question the SAT will include 1.5% as one of its answer choices to try to fool you.

This example is just one of the ways that the SAT might test your ability to work with graphs. There’s no way for us to prepare you for all the different varieties of hybrid charts and graphs questions that might appear. However, the majority of these questions deal with means, medians, modes, or percentages. So if you are comfortable interpreting graphs and charts, and you understand means, medians, modes, and percentages, you should do fine on these questions.

Every once in a while, the SAT includes a chart or graph and then asks more than one question about it. These groups are almost never larger than three questions. One or two of those three will ask you to interpret the chart or graph. The others will ask you to perform operations on the data.