题目内容
脱式计算能简算得要简算.
①1.8÷0.75+9.6÷2.4
②6.7+++2.3
③19×(+)×6
④×+3×+×.
解:(1)1.8÷0.75+9.6÷2.4,
=2.4+4,
=6.4;
(2)6.7+++2.3,
=(6.7+2.3)+(),
=9+2,
=11;
(3)19×(+)×6,
=19×6+19×6,
=38+42,
=80;
(4)×+3×+×,
=×(+3+),
=×7,
=5.
分析:(1)按照先同时计算除法,再算加法顺序解答,
(2)运用加法交换律以及结合律解答,
(3)(4)运用乘法分配律解答.
点评:根据各数的特点选择并应用正确的计算方法是解答本题的关键.
=2.4+4,
=6.4;
(2)6.7+++2.3,
=(6.7+2.3)+(),
=9+2,
=11;
(3)19×(+)×6,
=19×6+19×6,
=38+42,
=80;
(4)×+3×+×,
=×(+3+),
=×7,
=5.
分析:(1)按照先同时计算除法,再算加法顺序解答,
(2)运用加法交换律以及结合律解答,
(3)(4)运用乘法分配律解答.
点评:根据各数的特点选择并应用正确的计算方法是解答本题的关键.
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