Terminated: unknown
As visible on the calculator’s picture, there’s only an MR key, no other memory keys. That’s because the = key acts as an M+ key. Use the MR key to read out the sum of all results and use the AC key to clears the calculator’s memory and start over.
Press any of the basic four function operators twice to have it repeat when pressing the = key. For example, to calculate 24 one can use the sequence 2 × × = = =.
The calculator claims that √-9 = -3.