簡便計算(5.2-4.6)X4.6-0.9

簡便計算(5.2-4.6)X4.6-0.9

(5.2-4.6)X4.6-0.9=0.6X4.6-0.9=0.6X4.6-0.6-0.3=0.6X(4.6-1-0.5)=0.6X3.1=0.6X(3+0.1)=0.6X3+0.1X0.6=1.86