Question

A={x:x belongs to N and sum of digits of x is same as the number of digits of x}​

Answer 1

Answer:

A = { 20, 300, 120, .....................}

Step-by-step explanation:

here hear the condition for X is that the number of digits should be equal to the sum of the digits in that number. for for example if we take 20 there are two digits in 20 and the sum of digits that is 2 + 0 is equal to 2 . so here the number of digits and the sum of digits is the same so here 20 can be taken as x which is a part of set A. there can be many such numbers like 300 120 etc. so we cannot limit the set.

hope it helps you