Let unit digit be x and hundred’s digit be y Number = x × 1 + 0 × 10 + y × 100 = x + 100 y Aste interchange of digits number = y × 1 + 100 × x= 100 x + y According to the question 100x + y – x – 100y = 198 99 (x – y) = 198 ∴ x – y = 2 Hence disterence = 2