How to add a calculator?

I'm trying to add a calculator, but the Assistant calculator doesn't show up. I am already using a calculator on the form

I checked your form and there's no Calculator widget added on it. Here's a guide how to add a widget:

1. Go to the More Fields tab, type and search for the Calculator widget. Drag and drop it to your form.

2. In the Calculator widget wizard, you can enable or disable the Auto-hide calculator number pad and change theme. Click the Add widget button when you're done.

Hope that helps. Let us know if you need further assistance. Thank you.