六年级奥数计算题

自己去买奥数书

计算：
（1）1／1×4＋1／4×7＋1／7×10＋1／10×13＋1／13×16
=1/3*(1-1/4+1/4-1/7+1/7-1/10+1/10-1/13+1/13-1/16)=5/16
（2） 1×2×3＋3×6×9＋7×14×21
————————————————
1×3×5＋3×9×15＋7×21×35
1x2x3x(3+7)
---------------
1x3x5x(3+7)

1x2x3
---------
1x3x5

6
----
15

2
----
5
（3）（3.91+24/7+6.09+46/7）*（2.125-1.125）+（1÷2/3-1.5）*6.04
=[(3.91+6.09)+(24/7+46/7)]*1+(3/2-1.5)*0.64
=[10+10]*1+0
=20
(4)14*24/7+0.65*8/13-2/7*14+5/13*0.65
=48-4+0.65*(8/13+5/13)
=44+0.65*1
=44.65
(5)41.2*8.1+11*9.25+53.7*1.9
=41.2*(10-1.9)+(10+1)*9.25+53.7*1.9
=412-41.2*1.9+92.5+9.25+53.7*1.9
=(53.7-41.2)*1.9+412+92.5+9.25
=12.5*(2-0.1)+412+92.5+9.25
=25-1.25+412+92.5+9.25
=25+412+92.5+(9.25-1.25)
=437+92.5+8
=437+100.5
=537.5
(6)1+4+7+10+.......+2008=
(1+2008)×【(2008-1)÷3+1