The Cadastro Específico do INSS (National Social Security Institute) (CEI), is used by individuals who are legally equivalent to companies, that is, natural persons, common, but who, in exercising their activities, have a status of company.
The CEI generate 12 digit numbers, and the last digit is the verify number obtained from sum and subtract from others.
The CEI generator verify multiplying the last eleven numbers for each weigth, sum all of them and now sum the unity digit and tens digit, lastly get the unity digit got on the last sum and subtract from 10. And this is the verify digit of CEI generated from generator.
This tool was developed for programmers and testers who have the constant need to enter different CEI numbers in developing forms.