Question

10*12/1+12*14/1+14*16/1+16*18/1怎么算

Answer 1

1/10*12+1/12*14+1/14*16+1/16*18

=(1/10-1/12)/2+(1/12-1/14)/2+(1/14-1/16)/2+(1/16-1/18)/2

=(1/10-1/18)/2

=4/180

=1/45