(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与6.02的积,和是多少?多简便运算
问题描述:
(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与6.02的积,和是多少?
多简便运算
答
28.82 19 33.3 33.6
答
(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×...