The human hand played an important part inthe development of stone tools. Stone artifactsfrom 2.5M years ago help humans to hunt fishmeat and to make fire. In the period before thedevelopment of the stone ax, the humanancestor’s wrist weak. The bone passes throughthe palm of the middle finger and the wrist, andkeeps the wrist stable when a person holds a smallobject between the thumb and the finger. So theycan not use the wrist to hold some small things.With the time pass, after entering the NeolithicAge, the use of human hands more dexterous.Human can use stone to grind into a knife, shovel,spinning wheel and so on tools or weapons. So thestone tools make their life easy from 2.5M yearsago. If humans have 6 fingers instead of 5 fingers, Ithink they might have some advantage. Like theycan use the extra finger to do something else. Thegrip should be stronger, playing basketball seemsto be more control of the ball. The keyboard willbe based on six fingers design. And the speed oftyping will be faster. But if we use 5 fingers,everything will be simple, cause the environmentrelated. With the evolution of mankind, five fingerswere more suitable for human survival, thenevolved into five fingers. It is like the duck handwere four. It also to adapt to the environment. Ourancestor use stone tools by 5 fingers, and if theyuse it by 6 fingers, the hunting speed will be fasterthan before. If we all have 6 fingers, we may seethe world changed. People can hold 4 or 5 glasseson our hand. The technology will adapt to 6fingers. Therefore, 6 fingers would be convenienceand speed up than nowadays human