For example, 4 1- 19.

Ranked tenth is 4- 1. Originally 4- 1 should be equal to 3, but why is the final result 22? Because the number 1-9 is not enough, he borrowed a number from the higher order 4, so you should subtract one more number 1 when calculating 4- 1, because your lower order "1" borrowed a number from you, so it should be 4-1-/.