Answer 1

I am not sure, whether you want that:
https://code.sololearn.com/WzXibrT61Rev/?ref=app
but this code is from the tutorial, just changed from + to -....

Answer 2

I don't know angularJs but check if this is what you want...(JavaScript)

https://code.sololearn.com/WFsK0L7SQBSW/?ref=app

Answer 3

تا

Answer 4

🤨🤨🤨👍👍🏻