How the NPOST math section works
Each question is a small situation from police work followed by a question: the total value of items listed in a burglary report, what is left when one item is taken off that total, how many visits an officer makes in a year, the average miles per shift once one long shift is removed. No law or police knowledge is needed; everything you need is in the question.
You get 20 minutes for 20 questions, so a minute each, and you work on scratch paper in the booklet. Your score is the percentage you get right, with nothing taken off for a wrong answer. Within the 20 minutes you can go back and change answers in this section, but not once the section has ended.
How to solve each problem
Use the same four steps on every question:
- Read the last sentence first, so you know exactly what is being asked: a total, a difference, an average or a rate.
- Underline the numbers you need and cross out the ones you do not. Watch for words like EXCEPT, each, per and remaining.
- Estimate with rounded numbers. With five options spread apart, a rough answer often rules out three or four of them.
- Work it out on paper, then check the answer makes sense: an average cannot be bigger than the largest value, and a part cannot be bigger than the total.
Worked examples
A burglary report lists a bicycle worth $240, a tablet worth $385, a watch worth $175 and a backpack worth $60. What was the total value of the stolen items? (A) $760 (B) $820 (C) $860 (D) $900 (E) $960. Estimate first: about 250 + 400 + 175 + 60 is roughly 885, so the answer sits near the middle. Exactly: 240 + 385 = 625, plus 175 is 800, plus 60 is 860. The answer is C. If the next question asks for the value of everything except the watch, take it off the total you already have: 860 minus 175 is 685.
Officer Reyes drove 270 miles over six shifts. On one shift she drove 70 miles. What was her average on each of the other shifts? Take the long shift off first: 270 minus 70 is 200. That covers five shifts, not six, so divide by 5: 200 ÷ 5 = 40 miles. The common slip is to divide the full 270 by 6, which gives 45, and slips like that are exactly what the wrong options are made of.
Tips for the real math section
- Practise long division and multiplication by hand before the test. Without a calculator, speed on paper is the whole section.
- Check how many items an average is spread over. "The other days" or "except" changes the count.
- Keep units straight: dollars against dollars, minutes against minutes, and 60 minutes in an hour, not 100.
- If a problem is taking more than about 90 seconds, mark your best estimate and move on. You can come back while the section clock is running.
- Answer all 20. A guess has a one in five chance; a blank has none.
Practise NPOST math on CogniPrep
Our math drill gives you 20 problems in 20 minutes, four each of totals, differences, averages, rates and percentages, with five options in ascending order and no calculator. The problems are generated fresh each time, so you never see the same paper twice, and the wrong options are built from common slips so the feedback can name the one you keep making. You can move back and forth and change answers until time runs out. Your result is your percentage correct, shown beside the 70% minimum Iowa sets for each section. The drill is free.