解题思路:(1)(4)先算乘法,再算加法;
(2)先算乘法,再算减法;
(3)根据减法的性质简算;
(5)运用乘法分配律简算;
(6)先把3.2分解成8×0.4,再运用乘法结合律简算.
(1)19.4×6.1+2.3
=118.34+2.3
=120.64;
(2)5.67×0.21-0.62
=1.1907-0.62
=0.5707;
(3)10-0.72-0.28
=10-(0.72+0.28)
=10-1
=9;
(4)0.8×4.3+1.25
=3.44+1.25
=4.69;
(5)63.8×1.57+1.57×36.2
=(63.8+36.2)×1.57
=100×1.57
=157;
(6)3.2×0.25
=8×0.4×0.25
=8×(0.4×0.25)
=8×0.1
=0.8.
点评:
本题考点: 小数四则混合运算.
考点点评: 本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.