Step 1

Changed pending operator to start with a question mark
Step 2a

Created a BOOL to clear all
Step 2b

Created a BOOl that detects the equals sign
Step 2c

Created a BOOL that can detect plus, minus, times, divide, and mod operations
Step 3a

Wrote the code for register arithmetic key
Step 3b

Created the compute and display method
Step 4a

Declared and implemented clear accumulator and clear operation methods
Step 4b

Cleaned up code by using clear screen method, clear accumulator method, and clear operation method
Step 4c

Deleted synthesis foo lines
Fixed the switch statement in the computeAndDisplayResult method
Step 5

Implemented all of the methods so calculator can calculate