∵1000=10*10*10
∴1000的立方根=10
1000000=100*100*100
∴1000000的立方根=100
∵0.001=0.1*0.1*0.1
∴0.001的立方根=0.1
0.000001=0.01*0.01*0.1
∴0.000001的立方根=0.01