用你喜欢的方法计算.
1000-25×16+98??????
34×21+166×21?????????
48×(129+56)-345
(85+79)×(85-79)
968-(118×24-1890)
156×37-56×37.
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解:(1)1000-25×16+98,
=1000-25×4×4+98,
=1000-400+98,
=698;
??????
(2)34×21+166×21,
=(34+166)×21,
=200×21,
=4200;
????????
(3)48×(129+56)-345,
=48×185-345,
=8880-345,
=8535;
(4)(85+79)×(85-79),
=164×6,
=984;
(5)968-(118×24-1890),
=968-(2832-1890),
=968-942,
=26;
(6)156×37-56×37,
=(156-56)×37,
=100×37,
=3700.
解析分析:(1)把16看作4×4,先算乘法,然后从左往右依次运算;
(2)(6)运用乘法分配律简算;
(3)先算括号内的,再算乘法,最后算减法;
(4)两个括号同时计算,最后算乘法;
(5)先算括号内的乘法,再算括号内的减法,最后算括号外的减法.
点评:此题主要考查整数的四则混合运算的运算顺序和应用运算定律进行简便计算.