半径是2米的圆的周长与圆的面积相等. .(判断对错)
× =16× =× =1.
× = ×=0.1× = ×12=1.
因为×=1,所以是倒数,也是倒数. .
最小的合数的倒数是 ,0.25的倒数是 × =× =× = ×0.3=1.
一个数的倒数一定和它本身不相等 .