# Number Properties Puzzle – Challenge 8

This is a great math challenge about number properties. This math puzzle is a great refresher for those who love mathematics and critical thinking challenges. Let's challenge your brain!

## Challenge:

The number 10 has four different factors: 1, 2, 5, 10. What is the smallest 2 digits number that has exactly three positive factors?

### The Absolute Best Book to challenge your Smart Student!

The correct answer is 25.

Each prime number has exactly 2 factors, 1 and the number itself. To find the smallest 2 digits number, n, that has exactly three positive factors, we need to find an odd perfect square number. Why?

The factors of number n are 1, n and a prime number. Let’s consider the smallest prime numbers:

2: If 2 is a factor of n, then n should be 4 (1×2×2). This is not the answer. Since, n should be a 2 digits number.

3: If 3 is a factor of n, then n should be 9 (1×3×3). This is not the answer!

5: If 5 is a factor of n, then n should be 25 (1×5×5). Bingo!

The Absolute Best Books to Ace AlgebraOriginal price was: $29.99.$19.99Current price is: $19.99.Original price was: $29.99.$14.99Current price is: $14.99.Original price was: $29.99.$14.99Current price is: $14.99.Satisfied 1 StudentsOriginal price was: $24.99.$14.99Current price is: $14.99.Satisfied 92 StudentsOriginal price was: $24.99.$15.99Current price is: $15.99.Satisfied 125 Students

## Related to This Article

### More math articles

- FREE CLEP College Algebra Practice Test
- How to Prepare for the TABE Math Test?
- 3rd Grade ILEARN Math Worksheets: FREE & Printable
- Top Calculators for the TASC 2023: Quick Review
- 10 Most Common 5th Grade MAP Math Questions
- Bеѕt Digital Pеn Tablet fоr Onlinе Mаth Teaching in 2024
- 10 Most Common SSAT Upper-Level Math Questions
- How to Use Substitution to Solve a System of Equations: Word Problems
- Volume of Cubes
- Top 10 Tips You MUST Know to Retake the ATI TEAS Math

## What people say about "Number Properties Puzzle – Challenge 8 - Effortless Math: We Help Students Learn to LOVE Mathematics"?

No one replied yet.