Spoiler
1) just convert the field to type "double". Or use a formula tool and use the function toNumber()
2) cleanse it to remove letters and punctuation and then trim it
3) use the if condition and string functions like sub-string and length in a formula tool
4) again, use a combination of if condition with sub-string and length functions in a formula tool
Going to do a few more Beginner challenges before moving on to Intermediate ones.
Since I am using these challenges to study for the Core Exam, I've been recording my study session and putting them online to help keep myself accountable everyday! It's not the highest quality video, but I do talk through my thought process live and try to solve the challenge.
