Gabriela-
For the 3rd question, use the following for the advanced question option "Question validation equation":
sum(self) <= sum(that.numcriancas)
And for "Question validation tip", use something like:
The sum of values for this question must not be greater than that for the first question.
.
When you use "Show Question Logic", you will see the following formula, which is automatically generated from the equation
sum(self) <= sum(that.numcriancas)
sum(numescolarizadas_A_1, numescolarizadas_A_2, numescolarizadas_B_1, numescolarizadas_B_2, numescolarizadas_C_1, numescolarizadas_C_2) <= sum(numcriancas_A_1, numcriancas_A_2, numcriancas_B_1, numcriancas_B_2, numcriancas_C_1, numcriancas_C_2)