选择最合理的方法进行计算 99×244×-3÷1+1÷3.8×3+3.5(9-3.25)÷2+1.052÷[(5-3)×15][5-(9-4)×]÷1.
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解:
(1)99×24,
=(99+)×24,
=99×24+×24,
=2376+23,
=2399;
(2)4×-3÷1,
=4×-3×,
=(4-3)×,
=1×,
=;
(3)+1÷3.8×3+3.5,
=+×3+3.5,
=+1+3.5,
=1.5+3.5,
=5;
(4)(9-3.25)÷2+1.05,
=6÷2+1.05,
=+1.05,
=3;
(5)2÷[(5-3)×15],
=2÷[1×15],
=2÷[1×15],
=2÷22,
=;
(6)[5-(9-4)×]÷1,
=[5-4×]÷1,
=[5-]÷1,
=÷1,
=1.
解析分析:(1)根据乘法分配律进行简算;(2)根据乘法分配律进行简算;(3)先算除法,再算乘法,最后算加法;(4)先算小括号里面的减法,再算除法,最后算加法;(5)先算小括号里面的减法,再算中括号里面的乘法,最后算除法;(6)先算小括号里面的减法,再算中括号里面的乘法,再算中括号里面的减法,最后算除法.
点评:四则运算,先弄清运算顺序,然后再进一步计算即可,能简算的要简算.