Form Calculator

Hello,
I am looking for some help with building a form that needs to calculate a total based on user input. In the attached screenshot, the user would enter a number. After this is entered, that number would be multiplied by 20 and the result would appear in the “0” text box. Thoughts?

Have a look at Yisrael’s own tutorial here.
https://www.grampsworkbench.com/examples
Go to the Attendance example.
https://www.grampsworkbench.com/Examples/Attendance-Fees

Plus, have a read of this very recent post as well.
https://www.wix.com/corvid/forum/community-discussion/help-with-yisrael-s-calculator-example/p-1/dl-5e7685f0e707fd00344efb4f?commentId=5e7685f0e707fd00344efb4f&origin=notification&postId=5e75a51c23f7740017cd4d54