Dúvida para selecionar "meia pizza"

Gostaria de criar uma condição que quando o usuário escolhesse um pizza "grande" com a opção "meia" no campo "quantidade", os outros campos de pizza só ficassem disponíveis com a opção "grande' e o campo "quantidade" ficasse disponível apenas a opção "meia". 

Hi,

Unfortunately, I'm not sure if I understand your concern correctly.

But based from the translation, it seems like you want to conditionally set some fields and values on them. Here are some guides that may help:

1. To set conditions to your forms, you can follow this guide: http://www.jotform.com/help/57-Smart-Forms-Using-Conditional-Logic 

2. To perform calculations to your fields, you can follow this guide: http://www.jotform.com/help/259-How-to-perform-calculation-in-the-form 

3. If you would like to assign calculation values on your fields like dropdowns, checkboxes and radio buttons, you can do that by checking this guide: http://www.jotform.com/help/301-How-to-Assign-Calculation-Value 

If you need further assistance on this, please do provide us more details of how your form should work.

I hope that helps.