用遞等式計算,能簡算的要簡算.
(1)100.18-9.6+18.53
(2)0.963+23.89-0.063
(3)2.5×0.3÷2.5×0.3
(4)2.8×10.1
(5)51×1.2-1.2
(6)0.36×(15.23-9.63)
解:(1)100.18-9.6+18.53,
=90.58+18.53,
=109.11;
(2)0.963+23.89-0.063,
=(0.963-0.063)+23.89,
=0.9+23.89,
=24.79;
(3)2.5×0.3÷2.5×0.3,
=2.5÷2.5×0.3×0.3,
=1×0.3×0.3,
=0.09;
(4)2.8×10.1,
=2.8×(10+0.1),
=2.8×10+2.8×0.1,
=28+0.28,
=28.28;
(5)51×1.2-1.2,
=(51-1)×1.2,
=50×1.2,
=60;
(6)0.36×(15.23-9.63),
=0.36×5.6,
=2.016.
分析:(1)從左往右依次計算;
(2)運用加法交換律與結(jié)合律簡算;
(3)為計算簡便,可調(diào)整一下運算順序,即2.5÷2.5×0.3×0.3,計算即可;
(4)把10.1看作10+0.1,運用乘法分配律簡算;
(5)運用乘法分配律簡算;
(6)先算括號內(nèi)的,再算括號外的.
點評:此題考查了小數(shù)的四則混合運算,注意運算順序和運算法則,靈活運用所學(xué)的運算定律簡便計算.