Daniel Kahneman posed the following question to college students at Princeton and the University of Michigan: “A bat and ball cost $1.10. The bat costs $1 more than the ball. How much does the ball cost?” What is the answer?
If you are like more half of some very bright students polled, then you incorrectly answered $.10. At the very least, you almost certainly initially thought of $.10 as the answer, before you started to think more critically rather than let your "intuitive math skills" dictate the answer. This wasn't an exercise in math skills as the math involved is simple addition and subtraction. It was an experiment demonstrating how the mental shortcuts we take, often unconsciously, result in inaccurate information.
The answer is $.05. If the bat cost $1.05 and the ball cost $.05, then the bat cost $1.00 more than the ball ($1.05-$.05=$1.00).