create more exercise content

[bxie]

Create more exercises for Codeitz by either making new content or splitting previous exercises (see comments in exerciseID of parameters GSheet).

Exercises to split:

• [x] var swap/ read
• [x] findMinMax/ read
• [x] digit processing/ read
• [x] float equality/ read

Concepts which need more exercises (each concept needs >=3)

• [ ] relational op read
• [ ] arith op read
• [ ] arith op write
• [ ] var write
• [ ] print read
• [ ] print write
• [ ] find min/max write
• [ ] float equality write
• [ ] digit processing write

It would be ideal for each concept (where read and write are different concepts) to have 2-4 exercises.

[bxie]

supported in usability tests

[YuxinZhangChristina]

exercises listed above have been split and updated on Gsheet_exercise_info