1-how can i limit the number for 2 question ?
i want user only enter the number greater or equal then number ( before question (Q8.3))
i write this code but cant work :

((Q84_1_1)-(Q83_1_1) >= 0 ) or ((Q84_1_3)-(Q83_1_3) >= 0 ) or
((Q84_2_2)-(Q83_2_2) >= 0 ) or ((Q84_3_2)-(Q83_3_2) >= 0 )

2- how can i force user to enter number between X and Y (2 numbers)

any help ?