What is the Number?

This classic two-digit number riddle is a great way to engage your critical thinking and algebraic skills. The puzzle states: "I am a 2-digit number. If you swap my digits, the new number is 45 less than me. My digits add to 9. What number am I?" To solve it, you can let the tens digit be x and the units digit be y. Then the number is 10x + y, and swapping digits gives 10y + x. According to the riddle: (10x + y) - (10y + x) = 45 Simplifying: 9x - 9y = 45 x - y = 5 Also, the digits add up to 9: x + y = 9 By solving the system: Adding the equations: (x - y) + (x + y) = 5 + 9 -> 2x = 14 -> x = 7 Substitute x =7 in x + y = 9: 7 + y = 9 -> y = 2 Therefore, the number is 72. Puzzles like these help sharpen algebraic thinking and are often used in educational settings to prepare students for exams and develop logical reasoning. I found that working through such riddles regularly improves not just math skills but also confidence in problem-solving. Plus, it’s fun to see how simple algebraic expressions make sense of what seems like a tricky riddle at first glance. If you enjoy this type of problem, try creating your own digit-based riddles or explore more complex puzzles involving numbers. Engaging with these encourages a deeper understanding of number properties and can be a great activity for learners of all ages.