計(jì)算下面各題,能簡(jiǎn)算的要簡(jiǎn)算.
8.56×2.7+1.44×2.7 1.25×2.5×4×0.8
(1.79+1.2×0.1)÷0.25 5.8÷[8×(1.8-1.3)].
解:
(1)8.56×2.7+1.44×2.7,
=(8.56+1.44)×2.7,
=10×2.7,
=27;
(2)1.25×2.5×4×0.8,
=(1.25×0.8)×(2.5×4),
=1×10,
=10;
(3)(1.79+1.2×0.1)÷0.25,
=(1.79+0.12)÷0.25,
=1.91÷0.25,
=7.64;
(4)5.8÷[8×(1.8-1.3)],
=5.8÷[8×0.5],
=5.8÷4,
=1.45.
分析:(1)根據(jù)乘法分配律進(jìn)行簡(jiǎn)算;
(2)根據(jù)乘法交換律和結(jié)合律進(jìn)行簡(jiǎn)算;
(3)先算小括號(hào)里面的乘法,再算小括號(hào)里面的加法,最后算除法;
(4)先算小括號(hào)里面的減法,再算中括號(hào)里面的乘法,最后算除法.
點(diǎn)評(píng):四則混合運(yùn)算,先弄清運(yùn)算順序,然后再進(jìn)一步計(jì)算即可,能簡(jiǎn)算的要簡(jiǎn)算.