计算下面各题,能用简便算法的用简便算法. ①3871-(1080-740)×7 ②5175÷207+102×9 ③0.9+1.08+0.92+0.1 ④13.59-6.91-0.09 ⑤983×(3.8+2.2)+0.237×1000 ⑥0.8×(35+65)×5÷100 ⑦30-[17.8+(6.2+38÷10)].
第1个回答 2014-10-21
①3871-(1080-740)×7, =3871-340×7, =3871-2380, =1491; ②5175÷207+102×9, =25+918, =943; | |
③0.9+1.08+0.92+0.1, =(0.9+0.1)+(1.08+0.92), =1+2, =3; ④13.59-6.91-0.09, =13.59-(6.91+0.09) =13.59-7, =6.59; | |
⑤983×(3.8+2.2)+0.237×1000, =983×6+237, =5898+237, =6135; ⑥0.8×(35+65)×5÷100, =0.8×100×5÷100, =0.8×5×(100÷100), =4×1, =4; | |
⑦30-[17.8+(6.2+38÷10)], =30-[17.8+10], =30-27.8, =2.2; |