Substitution

I don't know if someone else came up with a name for this concept but I'm going to call it Substitution:

I'm going to ask you a simple question and I want you to try to answer it as quickly as you can. Here it goes:

I pressed the ON/OFF button on my alarm clock 3 times and on the third press, the clock truned off. Does that mean that before I started, the clock was on or off?

Everyone I know will answer this question eventually. However I don't know anybody who can answer it in less than five seconds.

Substitution is a way of thinking that helps you answer such a question much quicker. When given a question, you throw it away, and replace it with a much easier question that has the same answer.

For example, recognizing that pressing the ON/OFF button twice has no effect whatsoever on the final state of the clock, you replace the above question with:

I pressed the ON/OFF button on my alarm clock once, and after that the clock turned off. Does that mean that before I started, the clock was on or off?

Much easier to answer, no? What you did here is took a question, and stripped it from all the elements and circumstances that are irrelevant to its answer. What you ended up with is a core question. One which describes a different scenario, not the same as the one at hand, but much simpler, and conveniently leads to the same answer.

I can think of many examples in my daily life where substitution comes in handy, and I'll be posting some later. In the meanwhile I want you to think of examples yourself, and post them back here.