作业帮1/2+1/6+1/12+1/20+1/30+1/42= 2+4+6+...+2010= (5/9-5/6+1/4)÷(
来源：学生作业帮 编辑：作业帮 分类：数学作业 时间：2024/05/18 00:51:59
1/2+1/6+1/12+1/20+1/30+1/42= 2+4+6+...+2010= (5/9-5/6+1/4)÷(-1/36)= (-19 18/19)*38= 都用简便计算
1/2+1/6+1/12+1/20+1/30+1/42
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1-1/7
=6/7
2+4+6+...+2010
=2×(1+2+3+……+1005)
=2× [ (1+1004)×1004÷2 +1005 ]
=2× [ 1005×502+1005 ]
=2×1005×503
=2010×503
= 1011030
(5/9-5/6+1/4)÷(-1/36)
=(5/9)×(-36)-(5/6)×(-36)+(1/4)×(-36)
=-20+30-9
=10-9
=1
(-19 18/19)*38
=-1918×38÷19
=-1918×2
=-3836
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1-1/7
=6/7
2+4+6+...+2010
=2×(1+2+3+……+1005)
=2× [ (1+1004)×1004÷2 +1005 ]
=2× [ 1005×502+1005 ]
=2×1005×503
=2010×503
= 1011030
(5/9-5/6+1/4)÷(-1/36)
=(5/9)×(-36)-(5/6)×(-36)+(1/4)×(-36)
=-20+30-9
=10-9
=1
(-19 18/19)*38
=-1918×38÷19
=-1918×2
=-3836
1/2+1/6+1/12+1/20+1/30+1/42= 2+4+6+...+2010= (5/9-5/6+1/4)÷(
小学六年级数学题[用简便方法计算] 2/1+6/1+12/1+20/1+30/1+42/1+56/1+72/1=?5/4
1+1/2-5/6+7/12-9/20+11/30-13/42+15/56=?
1又2/1-6/5+12/7-20/9+30/11-42/13=?
1+1/2-2-5/6+3+1/12-4-19/20+5+1/30-6-41/42+7+1/56-8-71/72+9+1
1+2又1/6+3又1/12+4又1/20+5又1/30+6又1/42+7又1/56+8又1/72+9又1/90=
已知1-2/1=2/1,1/2-3/1=6/1,3/1-4/1=12/1,4/1-5/1=20/1,5/1-6/1=30
(1+1/3+1/5+1/10+1/15+1/30)/(1/2+1/4+1/6+1/12+1/20+1/60)=R
1又1/6+2又1/12+3又1/20+4又1/30+5又1/42=?
简算:（1+1/3+1/5+1/10+1/15+1/30）÷（1/2+1/4+1/6+1/12+1/20+1/60）＝?
（1+1/3+1/5+1/10+1/15+1/30）÷（1/2+1/4+1/6+1/12+1/20+1/60）
已知2分之1=1-2/1,6/1=2/1-3/1,12/1=3/1-4/1,20/1=4/1-5/1,30/1=5/1-