考點(diǎn):小數(shù)四則混合運(yùn)算,運(yùn)算定律與簡便運(yùn)算
專題:運(yùn)算順序及法則,運(yùn)算定律及簡算
分析:(1)(4)(6)根據(jù)乘法分配律進(jìn)行計(jì)算;
(2)先算乘除法,再算加法;
(3)變形為(97.73-17.73)-(4.9+5.1)計(jì)算;
(5)先算小括號(hào)里面的加法,再變形為5.4÷(4.8÷0.8)計(jì)算.
解答:
解:(1)102×4.5
=(100+2)×4.5
=100×4.5+2×4.5
=450+9
=459
(2)0.01+3.75×0.8÷0.25
=0.01+3÷0.25
=0.01+12
=12.01
(3)97.73-(17.73+4.9)-5.1
=(97.73-17.73)-(4.9+5.1)
=80-10
=70
(4)(1.25+12.5+125)×8
=1.25×8+12.5×8+125×8
=10+100+1000
=1110
(5)5.4÷(3.94+0.86)×0.8
=5.4÷4.8×0.8
=5.4÷(4.8÷0.8)
=5.4÷6
=0.9
(6)7.8×6.9+2.2×6.9
=(7.8+2.2)×6.9
=10×6.9
=69
點(diǎn)評(píng):考查了運(yùn)算定律與簡便運(yùn)算,四則混合運(yùn)算.注意運(yùn)算順序和運(yùn)算法則,靈活運(yùn)用所學(xué)的運(yùn)算定律簡便計(jì)算.