Practice Math Questions for Praxis: Number Lines
Number line questions on the Praxis Core exam are usually pretty straightforward—they generally involve finding a missing number based on sequences or distances between points on the line.
The first practice question is a simple problem (finding a labeled coordinate on a number line based on the surrounding numbers). The second question is a little trickier (finding the coordinate of a point on the line based on its distance from other points).
- The distance from one labeled coordinate to the next on the number line is the same in every case. What is the value of y?
- For this number line, the distance from P to Q is half the distance from Q to R, and that distance is half the distance from R to S. The coordinate of P is 4, and the coordinate of R is 10. What is the coordinate of S?
Answers and explanations
- The correct answer is Choice (E).
The distance is the same from one labeled coordinate to the next in every case. Some of the labels indicate that each coordinate is 3 units away from the adjacent ones. The number that’s 3 more than 15 and 3 less than 21 is 18.
- The correct answer is Choice (A).
You can figure out the distance from P to S if you determine the distance from P to Q, because the distance from P to S is that distance, plus twice that distance, plus twice that.
The distance from P to R is 6 because 10 – 4 = 6. Q is in a position in which its distance from P is half its distance from R. The sum of those distances is 6. Therefore, the distance from P to Q is a number that can be added to twice itself to get 6. That number is 2.
2 + 2(2) = 6
You could use algebra to determine that, but it’s not necessary. Because the distance from P to Q is 2, you know that the distance from Q to R is 4 and that the distance from R to S is 8. The coordinate of P is 4, so the coordinate of S is 4 + 2 + 4 + 8, or 18.