题目内容
怎样简便怎样算.
(1)0.625×(8.3-2.5×0.12) | (2)3÷-÷3 | (3)3098+3098×99 |
(4)6.3×8.7+8.7×3.7 | (5)2.5×1.25×32 | (6)--. |
解:(1)0.625×(8.3-2.5×0.12),
=0.625×(8.3-0.3),
=0.625×8,
=5;
(2)3÷-÷3,
=7-,
=6;
(3)3098+3098×99,
=3098×(1+99),
=3098×100,
=309800;
(4)6.3×8.7+8.7×3.7,
=(6.3+3.7)×8.7,
=10×8.7,
=87;
(5)2.5×1.25×32,
=2.5×1.25×(4×8),
=(2.5×4)×(1.25×8),
=10×10,
=100;
(6)--,
=-(+),
=-1,
=.
分析:(1)先算新客户里面的乘法,再算小括号里面的减法,最后算括号外面的乘法;
(2)先算除法,再算减法;
(3)根据乘法分配律进行计算;
(4)根据乘法分配律进行计算;
(5)根据乘法交换律和结合律进行计算;
(6)根据连减的性质进行计算.
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.
=0.625×(8.3-0.3),
=0.625×8,
=5;
(2)3÷-÷3,
=7-,
=6;
(3)3098+3098×99,
=3098×(1+99),
=3098×100,
=309800;
(4)6.3×8.7+8.7×3.7,
=(6.3+3.7)×8.7,
=10×8.7,
=87;
(5)2.5×1.25×32,
=2.5×1.25×(4×8),
=(2.5×4)×(1.25×8),
=10×10,
=100;
(6)--,
=-(+),
=-1,
=.
分析:(1)先算新客户里面的乘法,再算小括号里面的减法,最后算括号外面的乘法;
(2)先算除法,再算减法;
(3)根据乘法分配律进行计算;
(4)根据乘法分配律进行计算;
(5)根据乘法交换律和结合律进行计算;
(6)根据连减的性质进行计算.
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.
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