prepareNumber function
Implementation
List<String> prepareNumber(String num) {
String out = num;
if (num.length % 3 == 1) {
out = '00$out';
} else if (num.length % 3 == 2) {
out = '0$out';
}
RegExp exp = RegExp(r'\d{3}(?=\d)');
return out.replaceAllMapped(exp, (match) => '${match.group(0)}*').split('*');
}