Question

数学计算题：

简便计算
360×72+36×280
=
99+11×19+11×80
=
2007×20082008—2008×20072007
=
28×11111+99999×8
=
986×89—987×88
=

Answer 1

解答：
360×72+36×280
=360×(72+28)=36000

99+11×19+11×80 =99+11 ×（19+80)=99+11×99=99×12=1188

2007×20082008—2008×20072007
=2007×2008×(10001-10001)=0

28×11111+99999×8
=11111×(28+72)=1111100

986×89—987×88
=(987-1)×(88+1)-987×88=987×88+987-88-1-987×88=987-89=898

Answer 2

360×72+36×280
=36×720+36×280
=36×(720+280)
=36×1000
=36000

99+11×11+11×80
=11×9+11×11+11×80
=11×(9+11+80)
=11×100
=1100

2007×20082008—2008×20072007
=2007×2008×10001—2008×2007×10001
=0

28×11111+99999×8
=28×11111+11111×9×8
=28×11111+11111×72
=(28+72)×11111
=100×11111
=1111100

986×89—987×88
=986×(88+1)—987×88
=986×88+986×1—987×88
=986—987×88+986×88
=986—(987-986)×88
=986—88
=986—(100-12)
=986—100+12
=886+12
=898

Answer 3

360×72+36×280
=360×(72+28)=36000

99+11×19+11×80 =99+11 ×（19+80)=99+11×99=99×12=1188

2007×20082008—2008×20072007
=2007×2008×(10001-10001)=0

28×11111+99999×8
=11111×(28+72)=1111100

986×89—987×88
=(987-1)×(88+1)-987×88=987×88+987-88-1-987×88=987-89=898
要努力啊

Answer 4

=36×720＋36×280
=36×（720＋280）
=36×1000
=36000

=11×(9＋19＋80)
=11×108
=1188

=40304590056×2
=80608180112

=28×11111+11111×8×9
=11111×(28+72)
=11111×100
=1111100

=87754+86856
=174610