Explain how do you know that in * 6,273 = 6,273 the? will be 1

Are you asking that in the equation X*6,273=6,273 X will be one? If so you can know this because 1 times anything equals itself, one is the only number to do this, an example is 1 times 2 equals 2. what ever number that equals x must be multiplied by 6,273 and still equal 6,273. In multiplication 1 acts like zero dose in addition. If you have 5 cookies and you don't take away any (5-0) then you will still have 5 cookies. It would be silly to say you now have three cookies because we didn't take away any.