计算下列各题,能简算的要简算.
3.75×+×1.25
0.25×1.25×32++1+8(++)÷5.36-1.86-3.146.8×8+3.5×8-44.
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解:(1)3.75×+×1.25,
=(3.75+1.25)×,
=5×,
=3;
(2)0.25×1.25×32,
=0.25×1.25×8×4,
=(0.25×4)×(1.25×8),
=1×10,
=10;
(3)++1+8,
=(+8)+(+1),
=9+2,
=11;
(4)(++)÷,
=(++)×12,
=×12+×12+×12,
=3+10+2,
=15;
(5)5.36-1.86-3.14,
=5.36-(1.86+3.14),
=5.36-5,
=0.36;
(6)6.8×8+3.5×8-44,
=(6.8+3.5)×8-44,
=10.3×8-44,
=82.4-44,
=38.4.
解析分析:(1)(6)运用乘法分配律简算;
(2)先把32分解成4×8,再运用乘法结合律简算;
(3)运用加法交换了和结合律简算;
(4)先把除法变成乘法,再运用乘法分配律简算;
(5)根据连续减去两个数,等于减去这两个数的和简算.
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.