解题思路:(1)运用加法结合律,和减法的性质简算;
(2)运用乘法分配律简算;
(3)先算除法,再算加法,然后算减法;
(4)把2.4分解成8×0.3,然后再运用乘法结合律简算.
(1)13.25-0.8+1.75-1.2,
=(13.25+1.75)-(1.2+0.8),
=15-2,
=13;
(2)2.5×99+2.5,
=2.5×(99+1),
=2.5×100,
=250;
(3)10.36+4.8-16.5÷5,
=10.36+4.8-3.3,
=15.16-3.3,
=11.86;
(4)12.5×2.4,
=12.5×(8×0.3),
=(12.5×8)×0.3,
=100×0.3,
=30.
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: 运算定律是常用的简便运算的方法,要熟练掌握,灵活运用.