怎樣算簡(jiǎn)便就怎樣算.
12.7×99+12.7
25×32×0.125
(7.6×15+2.4×5)÷126
16.8-2.25-4.63.
解:(1)12.7×99+12.7,
=12.7×(99+1),
=12.7×100,
=1270;
(2)25×32×0.125,
=(25×4)×(8×0.125),
=100×1,
=100;
(3)(7.6×15+2.4×5)÷126,
=(114+12)÷126,
=126÷126,
=1;
(4)16.8-2.25-4.63.
=16.8-(2.25+4.63),
=16.8-6.88,
=9.92.
分析:(1)12.7×99+12.7,應(yīng)用乘法分配律進(jìn)行簡(jiǎn)算;
(2)25×32×0.125,轉(zhuǎn)化為25×4×8×0.125,應(yīng)用乘法結(jié)合律進(jìn)行簡(jiǎn)算;
(3)(7.6×15+2.4×5)÷126按照混合運(yùn)算的運(yùn)算順序和計(jì)算法則脫式計(jì)算;
(4)16.8-2.25-4.63.根據(jù)減法的運(yùn)算性質(zhì),a-b-c=a-(b+c)進(jìn)行簡(jiǎn)算.
點(diǎn)評(píng):此題主要考查小數(shù)四則混合運(yùn)算,注意運(yùn)算順序和運(yùn)算法則,靈活運(yùn)用所學(xué)的運(yùn)算定律、運(yùn)算性質(zhì)進(jìn)行簡(jiǎn)便計(jì)算.