解题思路:(1)从左往右依次计算.
(2)(5)(8)先算括号内的,再算括号外的.
(3)运用加法结合律简算.
(4)运用减法的性质简算.
(6)运用乘法交换律与结合律简算.
(7)运用除法的性质简算.
(1)6.25÷0.25×0.4
=25×0.4
=10
(2)68.04÷(0.21×3.6)
=68.04÷0.756
=90
(3)0.486+0.01+3.99
=0.486+(0.01+3.99)
=0.486+4
=4.486
(4)19.75-6.45-3.55
=19.75-(6.45+3.55)
=19.75-10
=9.75
(5)2.02×(1.027÷0.26)
=2.02×3.95
=7.979
(6)1.25×11×4×0.8
=(1.25×0.8)×(11×4)
=1×44
=44
(7)90÷25÷4
=90÷(25×4)
=90÷100
=0.9
(8)36÷(97.28÷0.32)
=36÷304
≈0.12
点评:
本题考点: 小数四则混合运算;运算定律与简便运算.
考点点评: 考查了小数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.