First number = 8 and the sum of the digits of the second number is 2+8=10.
Thus the difference of the first number and the sum of the digits of second number is 10−8=2.
Similarly, the sum of the digits of third number is 2+7=9.
Hence the sum of digits of fourth number should be 2 more than 9 i.e. 11
Hence, fourth number is 65.