Virtually all of the Math questions in the Praxis Core deal with numbers and quantity in some way. However, there is a subset of problems in Praxis Core Math that focus primarily on numbers and quantity, with little or no focus on other more complex aspects of mathematics.

The types of “pure number” questions fall into five subcategories on the Praxis Core:

- Understanding numerical expressions (exponential expressions, units, and measurements)
- Reading numbers from graphs and charts
- Equalities
- Basic math operations (multiplication, division, addition, subtraction)
- Basic math operations with fractions

Of the categories above, fraction problems are the most complex and varied. The rules for operations with fractions (including rations, proportions, and rational numbers) differ depending on the operation. This why the Magoosh TOEFL Blog offers a helpful three-part guide to fraction problems in Core Math.

The other four categories of number/quantity questions are relatively simple. In this post, we’ll look at one example from each of the four non-fraction categories listed above. At the end of each post, I’ll give an answer key.

## Practice question #1: Understanding numerical expressions

If there are approximately 37,200,000,000,000 cells in the adult human body, how many cells total are there in the bodies of 10 adults?

A) 3.72 X 10^9 cells

B) 3.72 X 10^11 cells

C) 3.72 X 10^13 cells

D) 3.72 X 10^14 cells

E) 3.72 X 10^15 cells

## Practice question #2: Reading numbers from graphs and charts

An ostrich ran 28 miles in 60 minutes. The graph above indicates the total number of miles the ostrich ran at 10-minute intervals. According to the graph, approximately how many miles did the ostrich run in the last 30 minutes of its trip?

A) 10

B) 15

C) 17

D) 20

E) 25

## Practice question 3: Equalities

In which of the following are the numbers ordered from greatest to least?

A) 2, 1/4, -1/3, -1/2, -3

B) -3, 2, -1/2, -1/3, 1/4

C) 1/4, -1/3, -1/2, 2, -3

D) 2, -3, -1/2, -1/3, 1/4

E) -3, -1/2, -1/3, 1/4, 2

## Practice question 4: Basic math operations

In the last step of a computation, Roger subtracted 100 instead of adding 10. What one number can Roger add to his final result of 6,090 so that the correct result of the computation is displayed on the calculator and he does not have to clear his calculator and start over?

A) 10

B) 80

C) 90

D) 100

E) 110

## ANSWER KEY:

- D
- D
- A
- E

## Notes about the answers:

The math operation in question 1 is extremely simple—just multiply a single number by 10. The real task here is to figure out how to express 372 trillion exponentially. Again in number two, the math problem is simple. All you need to do is subtract the number of miles at the thirty-minute mark from the number of miles at the 60-minute mark. What you’re really being tested on is your ability to extract the correct numbers from the infographic. In question 3, your job is to correctly understand inequalities between different fractions, whole numbers, positive numbers, and negative ones. Finally in question four, you need to understand a simple addition problem and correct a mistake in the final step of the problem.

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