（5）8.6×2.7+3.5×1.6（6）（0.19×5.4＋2.6×0.19）×12.5（7）9.99×2.22+3.34×3.33 （8）1.2除4.2的商，再加5與6.02的積，和是多少？多簡便運算

（5）8.6×2.7+3.5×1.6=（10-1.4）×2.7+3.5×1.6=10×2.7-1.4×2.7+7×0.8=27-1.4×2.7+1.4×4=27+1.4×（4-2.7）=27+1.4×1.3=27+1.82=28.82（6）（0.19×5.4＋2.6×0.19）×12.5 =0.19×（5.4+2.6）×12.5=0.19×…