PRINT
PRINT "分数を約分します。"
PRINT
INPUT PROMPT "分子は？ ":x
INPUT PROMPT "分母は？ ":y
PRINT
LET x0=x
LET y0=y
CALL YAKUB(x,y)
PRINT "  ";x0;"/";y0;" → ";x;"/";y
PRINT
END

EXTERNAL FUNCTION GCD(a,b)
DO
   LET r=MOD(a,b)
   IF r=0 THEN EXIT DO
   LET a=b
   LET b=r
LOOP
LET GCD=b
END FUNCTION 

EXTERNAL SUB YAKUB(Q,W)
LET E=GCD(Q,W)
LET Q=Q/E
LET W=W/E
END SUB