Required Mathematical Intelligence

Chapter 149 The Clever Magician
The magician said: "Just tell me a number, and I will know your shoe size and age. It must be related to yourself. Multiply your shoe size (whole number) by 2, add 39, and multiply Take 50, add 56, and finally subtract your own age."

After hearing this, Dong Rao quickly calculated that his shoe size is 25 and he was born in 1983. According to the requirements, the calculation is:
（25×2 39） 56-1983=2523
After he reported the number, the magician immediately told him: 23 years old this year, shoe size 25, and then some people reported the calculation results one after another, and the magician guessed right one by one without any mistakes.

Do you know why?

[Answer: Suppose the shoe size is X and the person was born in Y year, then:
(2X 39)×50 56-Y
=100X 2006-Y
The year is 2006, 2006-Y is the age, and the number above a hundred is the shoe size. ]
(End of this chapter)