五上数学《小数乘除法》简便运算归类
-
简介
五上数学简便运算归类‖小数乘除法 一、乘法交换律：a×b=b×a 2.5×4.8×0.4 =2.5×0.4×4.8 =1×4.8 =4.8 0.125×7.2×8 =0.125×8×7.2 =1×7.2 =7.2 0.5×3.69×2 =0.5×2×3.69 =1×3.69 =3.69 二、乘法交换律、结合律：a×b=b×a (a×b)×c=a×(b×c) 1.25×0.88×0.8 =0.88×(1.25×0.8) =0.88×1 =0.88 0.25×3.2×1.25 =(0.25×4)×(8×1.25) =1×1 =1 2.5×0.44×4 =0.44×(2.5×4) =0.44×10 =4.4 三、乘法分配律 (顺展型)：(a±b)×c= a×c±b×c (4+0.8)×2.5 =4×2.5+0.8×2.5 =10+2 =12 8.5×(10‑2) =8.5×10‑8.5×2 =85‑17 =68 (80‑8)×12.5 =80×12.5‑8×12.5 =1000‑100 =900
本年级热门下载
同类热门下载