0.16×9.85＋264×0.0985＋72＋0.985
=0.16×9.85＋2.64×9.85+72＋9.85×0.1
=0.16×9.85＋2.64×9.85＋9.85×0.1+72
=9.85×(0.16+2.64+0.1)+72
=9.85×2.9+72
=9.85×(3-0.1)+72
=9.85×3-9.85×0.1+72
=29.55-0.985+72
=100.565為什么這樣做解釋一下免得我以后也不會(huì)觀察都含有985這個(gè)數(shù),先整理在一起=0.16×9.85＋2.64×9.85＋9.85×0.1+72 化成同樣的含有9.85=9.85×(0.16+2.64+0.1)+72利用加法結(jié)合律.整理起來=9.85×2.9+72 >>>>>>>×2.9比較麻煩 化成×(3-0.1) =9.85×(3-0.1)+72=9.85×3-9.85×0.1+72=29.55-0.985+7=100.5654800/12.5/2.5/3.2=？ 簡(jiǎn)算4800/(12.5×2.5×3.2)=4800/(12.5×3.2×2.5)=4800/(12.5×8×0.4×2.5)=4800/[(12.5×8)×(0.4×2.5)]=4800/(100×1)=4800/100=48有幫助請(qǐng)采納 謝謝謝謝你你學(xué)習(xí)一定很棒