10 Z=INT(LOG(ZZ)/LOG(10)+.)
20 IFXX=0THENXR=0:RETURN
30 XL=INT(LOG(ABS(XX))/LOG(10)+.):XH=INT(10^XL+.):IFXL<0THENXH=1/INT(1/10^XL+.)
40 XR=VAL(LEFT$(STR$(XX/XH+SGN(XX)*5/ZZ+.),2+Z)+"E"+STR$(XL)):RETURN