## Task 3 - 040523

a) How many two-digit natural numbers are there where the difference between the two digits is 5?

b) For how many of these numbers is the number itself eight times as large as their digit sum, i.e., the sum of its two digits?
a) There are nine of these numbers, namely 16, 27, 38, 49, 50, 61, 72, 83, 94.

b) Only the number 72 satisfies the additional condition.