题目

用简便方法计算。 ①11.5×8.7-11.5×6.7 ②3.2×0.25 ③0.72×101 ④8.8×39+8.8 ⑤7.6×2.4+2.4×2.4 答案：①11.5×8.7-11.5×6.7 =11.5×（8.7-6.7） =11.5×2 =23 ②3.2×0.25 =（0.8×4）×0.25 =0.8×（4×0.25） =0.8×1 =0.8 ③0.72×101 =0.72×（100+1） =0.72×100+0.72×1 =72+0.72 =72.72 ④8.8×39+8.8 =8.8×（39+1） =8.8×40 =352 ⑤7.6×2.4+2.4×2.4 =2.4×（7.6+2.4） =2.4×10 =24

查看本题答案和解析