脱式计算.(能简单的要简算)
(1)(2+2+2+2)×0.25
(2)8×4×12.5×0.25(3)×[-(+0.25)](4)(5-3.75)÷(+)÷1.2.
网友回答
解:(1)(2+2+2+2)×0.25,
=(2×4)×0.25,
=2×(4×0.25),
=2×1,
=2;
(2)8×4×12.5×0.25,
=(8×12.5)×(0.25×4),
=100×1,
=100;
(3)×[-(+0.25)],
=×[-(+)],
=×[-],
=×,
=;
(4)(5-3.75)÷(+)÷1.2,
=1.25÷÷1.2,
=1.25×2÷1.2,
=2.5÷1.2,
=.
解析分析:(1)把括号内的算式写成2×4,然后运用乘法结合律简算;(2)运用乘法交换律与结合律简算;(3)先算小括号内的,再算中括号内的,最后算括号外的;(3)两个括号同时计算,原式变为1.25÷÷1.2,再把除法改为乘法,从左往右依次计算.
点评:考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.