Solution

The difference of square of second digit of first number and square of first digit of first number = second number. (7² - 3²) = 49 – 9 = 40. The difference of square of second digit of fifth number and square of first digit of fifth number = sixth number. (9² – 6²) = (81 – 36) = 45. Similarly, The difference of square of second digit of third number and square of first digit of third number = fourth number (9² – 4²) = (81 – 16) = 65.