4/11 x 12.1 x 7/11 x 0.5= 4/11 x 121/10 x 7/11 x 1/2= ( 4 x 121 x 7 x 1) / ( 11 x 10 x 11 x 2)= 3388 / 2420= 7/5 = 1.4
11分之4×12.1×11分之7×0.5=7/10
