If you want to plot numbers on to the Oric text screen, STR$(N) will result in the number being printed in green. Avoid this by plotting a space immediately after the STR$(N), PLOT is used in the program, but using the same X, Y co-ordinates. The routine below will result in 5 being printed in the current ink colour rather than green.
10 N = 5
20 PLOT 20,10,STR$(N)
30 PLOT 20,10,STR$(N)