For problems that have more than one step, a partial answer is the answer to one of the steps of the problem, but not to the whole problem. For example,

The correct answer to this question is C, 13 girls and boys, but you may have liked choices B, D, or E, which are all partial answers to this problem (choice A is just silly). Here’s why you might have chosen B, D, or E: choice B is the total number of passengers on the Tuesday bus; choice D is the total number of passengers on the Monday bus; choice E is the total number of passengers riding for both days. You have to calculate each one of these numbers to get the final answer (choice E divided by the number of days, 2). At any point during those calculations, you may have looked down and seen that a number you had calculated matched a number in the answer choices. Then you may have assumed you found the right answer. But, no, you didn’t.

Partial answers love to prey upon eager test takers who are in a hurry to get the right answer. Instead of paying careful attention to the question, these test takers get a number, see it in the answer choices, and immediately identify it as the correct answer. ACT knows about all these eager, jumpy test takers and deliberately plants partial answers throughout the Math Test.

On word problems, the last sentence of the problem usually tells you what the question is looking for. Consider rereading this last sentence once you’ve formulated your answer to make sure you did what the question asked.