整数乘法运算定律推广到小数
1.在得数相同的算式后面画“√”,不同的画“✕”。
(1)(2.8+1.6)×1.7 2.8×1.7+1.6×1.7 ( )
(2)7.4×(2+0.1) 7.4×2+0.1 ( )
2. 用简便方法计算下面各题。
0.25×8.645×4
9.76×0.73-0.76×0.73
8.7×201
答案提示
1.(1) √(2)✕
2.
0.25×8.645×4
=0.25×4×8.645
=1×8.645
=8.645
9.76×0.73-0.76×0.73
=(9.76-0.76)×0.73
=9×0.73
=6.57
8.7×201
=8.7×(200+1)
=8.7×200+8.7
=1748.7