When we approach a problem we create a kind of mental model that is based on how we were taught to solve such problems. Below is an arithmetic problem using matchsticks to form Roman numerals and operators (+, -, and =). The equation is incorrect.
Incorrect Equation PROBLEM
See if you can solve it by envisioning a solution in which only one matchstick is moved to create a correct equation. You can only move one matchstick once (but not remove it).
Many people have trouble with this problem because they learned in school that solving arithmetic problems is a matter of manipulating quantities. For example, many people play around with this problem by moving the matchsticks that change the numbers, for example by taking away the first matchstick forming the "one" in the Roman numeral IV, changing it to a V. This "learned" perspective of what an arithmetic equation is brings many people to a complete standstill and they declare the problem impossible.
The very knowledge of arithmetic prevents us from approaching the problem on its own terms. Consequently, our thoughts go around in circles. We waste time reapplying methods we’ve learned in the past we already know to be futile. Creative thinking is knowing how to look at problems in many different ways. Instead of looking to exclude possibilities, look for ways to include them. Creative thinking involves changing the way you’ve been taught to look at things. When you change the way you look at things, the things you look at change.
SOLUTION The problem is easily solved when you change your perspective about arithmetic and consider the operators (+, -, =) of the equation as well as the quantities. This will help you see the problem from a different angle. The solution lies in moving one matchstick to change the operators.