DAT/Variables
        LDA FIRST
        ADD SECOND //Change add to sub to turn the program to a subtraction version
        STA 97 //Not required, but helps in understanding the code a bit
        OUT 97 // If you don't use the line above, remove the '97' from this line and just use 'OUT'
        HLT
FIRST   DAT 12 // These can go above or below the HLT, but must be at the bottom of the program.
SECOND  DAT 23

        LDA FIRST
        ADD SECOND
        OUT
        HLT
FIRST   DAT 12
SECOND  DAT 23

        LDA FIRST
        ADD SECOND
        OUT
	LDA THIRD
	OUT
        HLT
FIRST   DAT 12
SECOND  DAT 23
THIRD DAT 45

	INP
	STA ANYWORD
	OUT ANYWORD
ANYWORD DAT

Countdown from 10 code:
LOOP    LDA X
        BRZ END
        OUT
        SUB Y
        STA X
        BRA LOOP
END     HLT
X       DAT 10
Y       DAT 1