Question

2．脫式計(jì)算，能簡(jiǎn)算的要簡(jiǎn)算．
①19.76÷5.2+2.3
②8.37÷0.39-4.47÷0.39
③0.37×8.4+7.1÷2.5
④0.4×5.62×2.5
⑤5.98÷2.3÷0.52
⑥2.7×0.43+0.34×2.7+2.7×1.23．

Answer 1

分析 ①首先計(jì)算除法，然后計(jì)算加法，求出算式的值是多少即可．
②首先用8.37減去4.47，求出差是多少；然后用所得的差除以0.39即可．
③首先計(jì)算乘法和除法，然后計(jì)算加法，求出算式的值是多少即可．
④根據(jù)乘法交換律和乘法結(jié)合律計(jì)算即可．
⑤從左向右依次計(jì)算，求出算式的值是多少即可．
⑥根據(jù)乘法分配律計(jì)算即可．

解答 解：①19.76÷5.2+2.3
=3.8+2.3
=6.1

②8.37÷0.39-4.47÷0.39
=（8.37-4.47）÷0.39
=3.9÷0.39
=10

③0.37×8.4+7.1÷2.5
=3.108+2.84
=5.948

④0.4×5.62×2.5
=0.4×2.5×5.62
=1×5.62
=5.62

⑤5.98÷2.3÷0.52
=2.6÷0.52
=5

⑥2.7×0.43+0.34×2.7+2.7×1.23
=2.7×（0.43+0.34+1.23）
=2.7×2
=5.4

點(diǎn)評(píng) 此題主要考查了小數(shù)四則混合運(yùn)算，注意運(yùn)算順序，注意乘法運(yùn)算定律以及除法的性質(zhì)的應(yīng)用．