binary – SPECIAL MULTIPLE HACKERRANK

I have been solving this problem from past no. of days?
But I have no clue neither I understand the editorial.
https://www.hackerrank.com/challenges/special-multiple/problem

You are given an integer N. Can you find the least positive integer X made up of only 9's and 0's, such that, X is a multiple of N?

Update

X is made up of one or more occurences of 9 and zero or more occurences of 0.

Input Format
The first line contains an integer T which denotes the number of test cases. T lines follow.
Each line contains the integer N for which the solution has to be found.

Output Format
Print the answer X to STDOUT corresponding to each test case. The output should not contain any leading zeroes.

Constraints
1 <= T <= 104
1 <= N <= 500

Sample Input

3
5
7
1
Sample Output

90
9009
9
Explanation
90 is the smallest number made up of 9's and 0's divisible by 5. Similarly, you can derive for other cases.