用递等式计算,能简算的要简算.
1÷[×(-)??×2+2÷113×+6÷16?????????3.5×98+3.5×2????7.05-4-1.05???×16-8÷.
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解:(1)1÷[×(-)],
=1÷[×],
=1÷,
=4;
(2)×2+2÷1,
=×+×,
=+,
=;
(3)13×+6÷16,
=13×+6×,
=(13+6)×,
=20×,
=;
(4)3.5×98+3.5×2,
=3.5×(98+2),
=3.5×100,
=350;
(5)7.05-4-1.05,
=(7.05-1.05)-4,
=6-4,
=2;
(6)×16-8÷,
=×16-8×,
=(16-8)×,
=2×,
=.
解析分析:(1)先算小括号内的,再算中括号内,最后算括号外的;(2)先算乘除,再算加法;(3)(6)把除法改为乘法,运用乘法分配律简算;(4)运用乘法分配律的逆运算简算;(5)运用加法交换律与结合律简算.
点评:此题是考查四则混合运算,注意运算顺序,仔细观察算式的特点,灵活运用一些定律进行简便计算.