A "simple square" is any integer greater than 1 that has only three positive integer factors - itself, its square root, and 1. Which of the following is a simple square?

(A) 121

(B) 100

(C) 81

(D) 64

(E) 33

Level of Difficulty E

The square root of 121 is 11, so if the only factors or 121 are 1, 11, and 121, then 121 is a simple square by definition. The only thing left to determine is whether 121 has any other factors. With a calculator, it's fairly easy to determine that there are no others. So, the only simple square listed is 121, or choice A.

- Fractions
- Area of Rectangle
- Visual Exercise
- Combined Rates
- 3D Solids
- Integers
- Simple Arithmetic
- Coordinate Pairs
- Signed Numbers
- Decimal Equivalents
- Displacement
- Symmetry
- Integers
- Triangles
- Integer Properties
- Cubic Functions
- Proportions
- Divisibility Rules
- Simple Squares
- Sets
- Sequences
- Rate Vectors
- Number Lines
- Word Problem
- Triangles
- Graph Theory
- 3D Solids
- Positive Integers
- Number Theory
- Even Integers
- Number Theory