解题思路:(1)(3)同分母分数相加,只把分子相加,分母不变;
(2)把1写成[12/12],按同分母分数相加减的方法计算;
(4)先算除法和乘法,再算减法;
(5)把24看作6×4,运用乘法结合律简算;
(6)把32看作4×8,运用乘法交换律与结合律简算;
(7)(8)运用乘法分配律简算;
(9)把98看作100-2,运用乘法分配律简算;
(10)先算小括号内的,再算中括号内的,最后算括号外的;
(11)先算括号内的,再算括号外的除法,最后算减法.
(1)[3/18]+[2/18]=[5/18],
(2)1-[4/12]=[2/3],
(3)[10/15]+[6/15]+[11/15]=[9/5],
(4)2200-200÷25×4,
=2200-8×4,
=2200-32,
=2168;
(5)24×25,
=6×4×25,
=6×(4×25),
=6×100,
=600;
(6)125×25×32,
=125×25×4×8,
=(125×8)×(25×4),
=1000×100,
=100000;
(7)165×65-65×65,
=(165-65)×65,
=100×65,
=6500;
(8)(90+125)×8,
=90×8+125×8,
=720+1000,
=1720;
(9)103×98,
=103×(100-2),
=103×100-103×2,
=10300-206,
=10094;
(10)500-(521+504)÷25,
=500-1025÷25,
=500-41,
=459;
(11)24×[(7480-6480)÷100],
=24×[1000÷100],
=24×10,
=240.
点评:
本题考点: 分数的加法和减法;整数的乘法及应用;整数四则混合运算.
考点点评: 此题考查了整数、分数的四则混合运算,注意运算顺序和运算法则,灵活运用运算定律或运算技巧进行简算.