Tested various micros running this FLOATING POINT program. It derives Pi to 20 decimal places. Interesting stats. 1 N=20: L=INT(10*N/3): DIM A(255): Z$="000000":T$="999999" 2 FOR I=1 TO L: A(I)=2: NEXT I: M=0: P=0: FOR J=1 TO N: Q=0: K=2*L+1 3 FOR I=L TO 1 STEP -1: K=K-2: X=10*A(I)+Q*I: Q=INT(X/K): A(I)=X-Q*K: NEXT I 4 Y =INT(Q/10): A(1)=Q-10*Y: Q=Y: IF Q=9 THEN LET M=M+1: GOTO 7 5 IF Q=10 THEN PRINT STR$(P+1);LEFT$(Z$,M);: P=0: M=0: GOTO 7 6 PRINT STR$(P);LEFT$(T$,M);: P=Q: M=0 7 NEXT J:PRINT STR$(P) #RC2014 : 14 (thank you JonV) #BBCMicro : 19 #AmstradCPC : 22 (thank you Devlin) #AcornElectron : 25 #C128 : 27 (fast mode - thank you Jonas H) #VIC20 : 36 #AcornAtom : 37 #CBMPET : 43 #C64 : 43 #Dragon32 : 44 #C16 : 46 #Altair8800 : 52 #MSX : 53 (thank you Pixel Purrito) #C128 : 56 (default "mode") #ZX80 : 57 #ZXSpectrum : 68 (thank you Adam) Edit: now ordered (seconds)