There are typically two types of number line problems:
- questions that show you an actual number line that require you to estimate and know properties of positive/negative numbers and decimals
- and questions that require you to translate a word problem into a number line.
When a question gives you a drawing of a number line, always look out for which points are between -1 and 1. Numbers whose absolute values are less than 1 are points B, C, D, E, F, G in the picture below. An important property to note is that when these points are multiplied with another point that is greater than 1, it makes that number smaller. Try it! Suppose G is 0.5 and H is 1.5. GxH is 0.75 which is smaller than H.
Another important property to note is what happens when you multiply two negative points together or when you multiply a negative and a positive point. Two negatives make a positive, meaning BxC gives you a positive number – either E, F or G because those points are positive and less than 1. A negative and a positive makes a negative. So BxG would either be point C or D. If you estimate what the values of those points are, you would be able to say with greater certainty too that BxG has to be point D.
Here’s another number line question where the line is given.
If there are 8 equal intervals between 0 and 1. What is the value of x? I would start counting the number of points until I get to the one labeled √x and realize that it is the point 6/8 which is also 3/4 . Since √x – 3/4 that means that x – 9/16.
The other type of question requires you to translate a word problem into a number line. Let’s start off with an easy word problem.
The number m – 4 is how much less than the number m + 5?
I would draw a number line like the one above. And let m equal a number. Suppose m=0. That means that m-4 = -4 and m+5=5. If I circle -4 and 5 on the number line and count the spaces in between, I would realize that they are 9 units apart.
Here’s a longer question. An important thing to note about “number lines” is that it generally refers to the x-axis. So if points A and C are located on a number line such that AC=6 that means you can draw and x-y graph and put A and C as two points on the x-axis, 6 units apart. If I then tell you that point E is also on the x-y plane and located so that AE=3, where could you put E? You could put E on the x-axis between A and C or to the left of A.
That means that if A is at (1,0) and C at (7,0), then E could be at (-2, 0) or (4,0)
Or E could not be on the number line if you put E 3 units above A or 3 units below A.
The most difficult type of number line problem is the word problem. Try sketching a map of the buildings and stores in the following problem: Highland High School lies exactly halfway between the East and West bridges of town. Piggy’s Pizza lies halfway between the high school and the East bridge. Paul’s sub shop lies somewhere between the high school and the West bridge. All buildings form a straight line from the East bridge to the West Bridge. If Paul’s is 8 miles from the West Bridge and Piggy’s is 13 miles from the East bridge, how far is it from Paul’s to Piggy’s?
Did you manage to get the figure above? Since Highland HS is exactly halfway between the bridges that means that it must be 26 miles – 8 miles = 18 miles between the high school and Pual’s sub shop. So Piggy’s to Paul’s = 13 miles + 18 miles = 31 miles.
If you liked the examples on the page, try a custom number line math SAT game on Grockit!






I’m happy to announce a recent improvement to a popular Grockit feature: In solo practice games, the questions that you see are selected based on your recent past performance. Grockit’s tailored Challenges — short assessment-oriented games that are unlocked over time — have a been popular way for students to benchmark their performance and get feedback on where they stand. We’ve now incorporated the core algorithm used to create Challenges into all solo practice games. Questions posed during these games are now selected in a way that takes into account both what you have seen in the past and how you’ve been doing on recent questions. We know that different students are stronger in different parts of a test, so you may notice that you’re seeing harder questions in one section than in another. You’ll find that the personalized question loader takes these variations into account.



