yu dont...log is the natural wae tu solv this problem... me suppose yu kan tri trial & repeet... 4^5=1024, so 4^10=1024*1024=1,048,576... 4^9=262,144,....4^8=65,536, so anser tween 8 & 9... 4^8.5=131,072...2 big, 7 so on... kood even tri a line approx from last 2 numbers yu hav