The smallest three-digit number whose value does not change when its digits are reversed is a palindrome. Palindromic numbers are the same when read forwards and backwards.

The smallest three-digit palindromic number is 101.

This number reads the same forwards and backwards, so its value does not change when its digits are reversed.

To get a number whose digits are the reverse of 203, we need to find the difference between this number and its reverse.

The number 203, when its digits are reversed, becomes 302.

To find what must be added to 203 to get 302, we subtract 203 from 302:

302−203=99302−203=99

So, 99 must be added to 203 to get a number whose digits are the reverse of the given number.

To create the greatest five-digit number using the digits 4, 2, and 0, we want to place the greatest digit in the leftmost position to maximize its value.

Since we're dealing with a five-digit number, the leftmost position can't be zero, otherwise, it would become a four-digit number.

So, the greatest five-digit number using the digits 4, 2, and 0 would start with the greatest digit available, which is 4. Then, we can place the next greatest digits, which are 2 and 0, in the remaining positions to maximize the value.

Arranging the digits in descending order from left to right, the greatest five-digit number would be:

Number=42,000Number=42,000

So, the greatest five-digit number using the digits 4, 2, and 0 is 42,000.

The greatest 6-digit number is 999,999.

To find its successor, we simply add 1 to it:

999,999+1=1,000,000999,999+1=1,000,000

So, the successor of the greatest 6-digit number, 999,999, is 1,000,000.