解题思路:(1)从左往右依次运算;
(2)运用减法的性质以及加法交换律与结合律简算;
(3)(4)通过数字转化,运用乘法分配律简算;
(5)先算小括号内的,再算中括号内的乘法,然后算中括号内的减法,最后算括号外的;
(6)两个括号同时计算.第一个括号先算乘法,再算加法;最后算括号外的除法.
(1)0.175÷0.25×4
=0.7×4
=2.8
(2)27.52-(7.7-2.48)+32.7
=27.52-7.7+2.48+32.7
=(27.52+2.48)+(32.7-7.7)
=30+25
=55
(3)3.2×(2.5+12.5)
=3.2×2.5+3.2×12.5
=0.8×(4×2.5)+0.4×(8×12.5)
=0.8×10+0.4×100
=8+40
=48
(4)6.8×3.7-3.7+37×0.42
=6.8×3.7-3.7+3.7×4.2
=(6.8-1+4.2)×3.7
=10×3.7
=37
(5)[(7.6-5.8)×0.8-1]×5.5
=[1.8×0.8-1]×5.5
=[1.44-1]×5.5
=0.44×5.5
=2.42
(6)(7.8+2.2×5)÷(4-3.06)
=(7.8+11)÷0.94
=18.8÷0.94
=20
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: 此题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.