(3/16-0,45)×0,8-0,21:0,2=

(0.1875-0.45)*0.8-0.21/0.2=-0.21+1.05=1.26

(3/16-0,45)*0,8-0,21/0,2=

(3/16-9/20)*4/5-(21/100)/(1/5)=

((15-36)/80)*4/5-(21*5/100)=

(-21*4)/(80*5)-105/100=

-21/100-105/100=

(-21-105)/100=

-126/100=

-1,26