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!
Related to This Article
More math articles
- The Complete Guide to 5 Best GED Math Study Guides
- Top 10 Tips to Overcome CLEP College Math Anxiety
- The Ultimate ASTB Math Course (+FREE Worksheets & Tests)
- Number Properties Puzzle -Critical Thinking 4
- The Ultimate 6th Grade MAAP Math Course (+FREE Worksheets)
- 10 Most Common 3rd Grade OST Math Questions
- 10 Most Common AFOQT Math Questions
- CLEP College Math FREE Sample Practice Questions
- Number Properties Puzzle -Critical Thinking 1
- 4th Grade SBAC Math Practice Test Questions
What people say about "Number Properties Puzzle – Challenge 8 - Effortless Math: We Help Students Learn to LOVE Mathematics"?
No one replied yet.