题目

用简便方法计算. (1) ( + ﹣ )÷ (2) ×100 (3) 0.125×0.25×64. 答案: ( 49 + 56 ﹣ 718 )÷ 136 =( 49 + 56 ﹣ 718 )×36 = 49 ×36+ 56 ×36﹣ 718 ×36 =16+30﹣14 =32 725 ×100 17 = 725 ×(100+ 17 ) = 725 ×100+ 725 × 17 =28+ 125 =28 125 ; 0.125×0.25×64 =0.125×0.25×(8×4×2) =(0.125×8)×(0.25×4)×2 =1×1×2 =2.
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