简便计算:(1)2+4+6+…+98+100 &n
来源:学生作业帮 编辑:拍题作业网作业帮 分类:数学作业 时间:2024/04/29 12:54:47
简便计算:
(1)2+4+6+…+98+100 | (2)7778×9999+6666×3333 |
(3)1÷50+2÷50+3÷50+…+99÷50 | (4)454+999×999+545 |
(5)20.14×31.5+2.014×317+201.4×3.68 | (6)59+7×590+29×59 |
(7)99×99+199: | (8)99999+9999+999+99+9 |
(9)197×198-196×199: | (10)2013×20142014-2014×20132013 |
(11)88+99×33+55. |
(1)2+4+6+…+98+100
=(2+100)×25
=2×25+100×25
=50+2500
=2550
(2)7778×9999+6666×3333
=7778×9999+2222×3×3333
=7778×9999+2222×9999
=9999×(7778+2222)
=9999×10000
=99990000
(3)1÷50+2÷50+3÷50+…+99÷50
=
1
50×(1+2+3+…+99)
=
1
50×(100×49+50)
=
1
50×4900+
1
50×50
=98+1
=99
(4)454+999×999+545
=(454+545)+999×999
=999+999×999
=999×(1+999)
=999×1000
=999000
(5)20.14×31.5+2.014×317+201.4×3.68
=201.4×3.15+201.4×3.17+201.4×3.68
=201.4×(3.15+3.17+3.68)
=201.4×10
=2010
(6)59+7×590+29×59
=59+70×59+29×59
=59×(1+70+29)
=59×100
=5900
(7)99×99+199
=99×99+99+100
=99×(99+1)+100
=99×100+100
=100×(99+1)
=100×100
=10000
(8)99999+9999+999+99+9
=(100000-1)+(10000-1)+(1000-1)+(100-1)+(10-1)
=100000+10000+1000+100+10-5
=111110-5
=111105
(9)197×198-196×199
=197×198-196×(198+1)
=197×198-196×198-196
=198×(197-196)-196
=198×1-196
=198-196
=2
(10)2013×20142014-2014×20132013
=2013×2014×10001-2014×2013×10001
=0
(11)88+99×33+55
=88+(100-1)×33+55
=88+3300-33+33+22
=88+22+3300
=110+3300
=3410.
=(2+100)×25
=2×25+100×25
=50+2500
=2550
(2)7778×9999+6666×3333
=7778×9999+2222×3×3333
=7778×9999+2222×9999
=9999×(7778+2222)
=9999×10000
=99990000
(3)1÷50+2÷50+3÷50+…+99÷50
=
1
50×(1+2+3+…+99)
=
1
50×(100×49+50)
=
1
50×4900+
1
50×50
=98+1
=99
(4)454+999×999+545
=(454+545)+999×999
=999+999×999
=999×(1+999)
=999×1000
=999000
(5)20.14×31.5+2.014×317+201.4×3.68
=201.4×3.15+201.4×3.17+201.4×3.68
=201.4×(3.15+3.17+3.68)
=201.4×10
=2010
(6)59+7×590+29×59
=59+70×59+29×59
=59×(1+70+29)
=59×100
=5900
(7)99×99+199
=99×99+99+100
=99×(99+1)+100
=99×100+100
=100×(99+1)
=100×100
=10000
(8)99999+9999+999+99+9
=(100000-1)+(10000-1)+(1000-1)+(100-1)+(10-1)
=100000+10000+1000+100+10-5
=111110-5
=111105
(9)197×198-196×199
=197×198-196×(198+1)
=197×198-196×198-196
=198×(197-196)-196
=198×1-196
=198-196
=2
(10)2013×20142014-2014×20132013
=2013×2014×10001-2014×2013×10001
=0
(11)88+99×33+55
=88+(100-1)×33+55
=88+3300-33+33+22
=88+22+3300
=110+3300
=3410.