sir in 1 example example is a faulty machine records the price and number of good purchased but mistackally reversed digit and record no is 63 less than actual and value of the record good was 696. sir in this after a- b get 7 you number is whether 92 or 81.so that number 92 or 81 is how coming is actually i dont getting so please sir can you explain it .how you got that number is 92 or 81 and its reversed digit is 29 or 18