能简算的要简算. 15.6-8.9+5.67.02+3.8+3.98+2.268.4-(4.7+8.4)35.8-(40-44.2)100-13.72-36.8247.35+16.88-7.35.
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解:(1)15.6-8.9+5.6,
=6.7+5.6,
=12.3;
(2)7.02+3.8+3.98+2.2,
=(7.02+3.98)+(3.8+2.2),
=11+6,
=17;
(3)68.4-(4.7+8.4),
=68.4-8.4-4.7,
=60-4.7,
=55.3;
(4)35.8-(40-44.2),
=35.8-40+44.2,
=35.8+44.2-40,
=80-40,
=40;
(5)100-13.72-36.82,
=100-(13.72+36.82),
=100-50.54,
=49.46;
(6)47.35+16.88-7.35,
=47.35-7.35+16.88,
=40+16.88,
=56.88.
解析分析:(1)按照从左到右的顺序计算;
(2)运用加法交换律和结合律简算;
(3)根据减法的性质简算;
(4)先去掉括号,再根据加法交换律简算;
(5)根据减法的性质简算;
(6)运用加法交换律简算.
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.