问题描述:
用简便方法计算:1.29+3.7+0.71+6.3 | 125×89×8 | 57×101-57 | 24×25×4 |
125×26+125×22 | 52×104 | 1569-(569+815) | 7.56-(1.56+3.72) |
最佳答案:
(1)1.29+3.7+0.71+6.3
=(1.29+0.71)+(3.7+6.3)
=2+10
=12;
(2)125×89×8
=125×8×89
=1000×89
=89000;
(3)57×101-57
=57×(101-1)
=57×100
=5700;
(4)24×25×4
=24×(25×4)
=24×100
=2400;
(5)125×26+125×22
=125×(26+22)
=125×48
=6000;
(6)52×104
=52×(100+4)
=52×100+52×4
=5200+208
=5408;
(7)1569-(569+815)
=1569-569-815
=1000-815
=185;
(8)7.56-(1.56+3.72)
=7.56-1.56-3.72
=6-3.72
=2.28.