计算
$0.2+0.8=$
$0.9+2.1=$
$4.6+5.4=$
$4.5-1.7=$
$1.5-0.7=$
$10-0.8=$
$13.5+6.5=$
$1-0.32=$
$3.8-0.8=$
$2.05-0.05=$
$2.5×4=$
$0.8×0.9=$
$4.6×0.2=$
$9×1.1=$
$0.12×6=$
$1.6×3=$
$0.9×0.5=$
$2.5×0.4=$
$4×0.25=$
$0.4×0.6=$
$1.2×0.3=$
$7×0.6=$
$0.25×8=$
$3.5×0.2=$
$2.4×0.5=$
$0.05×4=$
$1.8×0.2=$
$0.32×5=$
$1.1×0.9=$
$2.5×0.8=$

$0.2+0.8=1$
$0.9+2.1=3$
$4.6+5.4=10$
$4.5-1.7=2.8$
$1.5-0.7=0.8$
$10-0.8=9.2$
$13.5+6.5=20$
$1-0.32=0.68$
$3.8-0.8=3$
$2.05-0.05=2$
$2.5×4=10$
$0.8×0.9=0.72$
$4.6×0.2=0.92$
$9×1.1=9.9$
$0.12×6=0.72$
$1.6×3=4.8$
$0.9×0.5=0.45$
$2.5×0.4=1$
$4×0.25=1$
$0.4×0.6=0.24$
$1.2×0.3=0.36$
$7×0.6=4.2$
$0.25×8=2$
$3.5×0.2=0.7$
$2.4×0.5=1.2$
$0.05×4=0.2$
$1.8×0.2=0.36$
$0.32×5=1.6$
$1.1×0.9=0.99$
$2.5×0.8=2$

根据运算定律填空
$4.5×3.7=□×□$
$2.5×2.4×0.4=□×(□×□)$
$2.8×1.9+2.8×8.1=□×(□+□)$
$2.78×1.01=□×(□+□)$
$4.98×99+4.98=□×(□+□)$
$6.5+13.7+6.3=□+(□+□)$
$4.8×1.25=□×(□×□)$
$12.5×3.6×8=□×(□×□)$
$13×7.1+13×2.9=□×(□+□)$
$15×0.99=□×(□-□)$
$4.08+9×4.08=□×(□+□)$

$4.5×3.7=3.7×4.5$
$2.5×2.4×0.4=2.4×(2.5×0.4)$
$2.8×1.9+2.8×8.1=2.8×(1.9+8.1)$
$2.78×1.01=2.78×(1+0.01)$
$4.98×99+4.98=4.98×(99+1)$
$6.5+13.7+6.3=6.5+(13.7+6.3)$
$4.8×1.25=0.6×(8×1.25)$
$12.5×3.6×8=3.6×(12.5×8)$
$13×7.1+13×2.9=13×(7.1+2.9)$
$15×0.99=15×(1-0.01)$
$4.08+9×4.08=4.08×(1+9)$