三、计算下面各题,能简算的要简算。
$0.125 × 2 + 3.7 × \dfrac{1}{8} + \dfrac{1}{8} × 5.3$ $56 × (\dfrac{1}{8} + \dfrac{1}{7} + \dfrac{1}{14})$
$6.42 × 1.01 - 6.42$ $80.7 × 8.7 + 8.07 × 13$
$\dfrac{3}{5} × 153 - 0.6 × 53$ $\dfrac{8}{9} × [\dfrac{3}{5} - (\dfrac{9}{16} - \dfrac{2}{5})]$
$0.125 × 2 + 3.7 × \dfrac{1}{8} + \dfrac{1}{8} × 5.3$ $56 × (\dfrac{1}{8} + \dfrac{1}{7} + \dfrac{1}{14})$
$6.42 × 1.01 - 6.42$ $80.7 × 8.7 + 8.07 × 13$
$\dfrac{3}{5} × 153 - 0.6 × 53$ $\dfrac{8}{9} × [\dfrac{3}{5} - (\dfrac{9}{16} - \dfrac{2}{5})]$
答案
$\frac{11}{8}$ 19 0.0642 807 60 $\frac{7}{18}$
1. 小刚在计算$(25 + x) × 4$时,漏掉了括号,算成了$25 + 4x$。正确的结果与错误的结果相差多少?
答案
$(25+x)×4-(25+4x)=75$
2. 一段路已经修了$36\ \mathrm{km}$,比全长的$60\%$多$9\ \mathrm{km}$,这段路全长多少千米?
答案
$(36-9)÷60\% =45$(km)
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