A-A+
计算(能简算的要简算 写出计算过程)(1)53÷45-54×23(2)[447-(345-2
问题详情
计算(能简算的要简算,写出计算过程)
(1)
(2)[4
(3)12
(4)2+4
(5)12345678912-1234567890×1234567892
(6)
参考答案
(1)53÷45-54×23,
=53×54-54×23,
=(53-23)×54,
=1×54,
=54;
(2)[447-(345-223)×157]÷1415,
=[447-(195-83)×157]÷1415,
=[447-(195×157-83×157)]÷1415,
=[327-(577-407)]÷1415,
=[327-177]÷1415,
=157×1514,
=22598;
(3)12922÷612×[247+(24.4-24845)],
=12922÷612×[247+29],
=27322×213×17663,
=163;
(4)2+416+6112+8120+10130+12142,
=(2+4+6+8+10+12)+(16+112+120+130+142)
=(2+12)×6÷2+(12×3+13×4+14×5+15×6+16×7),
=42+(12-13+13-14+14-15+15-16+16-17),
=42+(12-17),
=42+514,
=42514;
(5)12345678912-1234567890×1234567892,
=12345678912-(1234567891-1)(1234567891+1),
=12345678912-(12345678912-1),
=12345678912-12345678912+1,
=1;
(6)13+115+135+163+…+1399,
=11×3+13×5+15×7+17×9+…+119×21,
=12×(1-13+13-15+15-17+17-19+…+119-121),
=12×(1-121),
=12×2021,
=1021.
考点:过程