在()里填上合适的数1.2=1*22+4=6=2*32+4+6=12=3*42+4+6+8=20=4*52+4+6+8+10=( )=( )*( )2+4+6+……+98+100=( )=( )*( )……2+4+6+8+……+n=( )=( )*( )2.1/2=1/1*2=1-1/21/6=1/2*3=1/2-1/31/12=1/3*4=1/3-1/41/20=1/
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![在()里填上合适的数1.2=1*22+4=6=2*32+4+6=12=3*42+4+6+8=20=4*52+4+6+8+10=( )=( )*( )2+4+6+……+98+100=( )=( )*( )……2+4+6+8+……+n=( )=( )*( )2.1/2=1/1*2=1-1/21/6=1/2*3=1/2-1/31/12=1/3*4=1/3-1/41/20=1/](/uploads/image/z/3973143-39-3.jpg?t=%E5%9C%A8%28%29%E9%87%8C%E5%A1%AB%E4%B8%8A%E5%90%88%E9%80%82%E7%9A%84%E6%95%B01.2%3D1%2A22%2B4%3D6%3D2%2A32%2B4%2B6%3D12%3D3%2A42%2B4%2B6%2B8%3D20%3D4%2A52%2B4%2B6%2B8%2B10%3D%EF%BC%88+%EF%BC%89%3D%EF%BC%88+%EF%BC%89%2A%EF%BC%88+%EF%BC%892%2B4%2B6%2B%E2%80%A6%E2%80%A6%2B98%2B100%3D%EF%BC%88+%EF%BC%89%3D%EF%BC%88+%EF%BC%89%2A%EF%BC%88+%EF%BC%89%E2%80%A6%E2%80%A62%2B4%2B6%2B8%2B%E2%80%A6%E2%80%A6%2Bn%3D%EF%BC%88+%EF%BC%89%3D%EF%BC%88+%EF%BC%89%2A%EF%BC%88+%EF%BC%892.1%2F2%3D1%2F1%2A2%3D1-1%2F21%2F6%3D1%2F2%2A3%3D1%2F2-1%2F31%2F12%3D1%2F3%2A4%3D1%2F3-1%2F41%2F20%3D1%2F)
在()里填上合适的数1.2=1*22+4=6=2*32+4+6=12=3*42+4+6+8=20=4*52+4+6+8+10=( )=( )*( )2+4+6+……+98+100=( )=( )*( )……2+4+6+8+……+n=( )=( )*( )2.1/2=1/1*2=1-1/21/6=1/2*3=1/2-1/31/12=1/3*4=1/3-1/41/20=1/
在()里填上合适的数
1.2=1*2
2+4=6=2*3
2+4+6=12=3*4
2+4+6+8=20=4*5
2+4+6+8+10=( )=( )*( )
2+4+6+……+98+100=( )=( )*( )……
2+4+6+8+……+n=( )=( )*( )
2.1/2=1/1*2=1-1/2
1/6=1/2*3=1/2-1/3
1/12=1/3*4=1/3-1/4
1/20=1/( )*( )=1/( )-1/( )
1/1*2+1/2*3+1/3*4+……+1/99*100=( )
例:1/2=二分之一
在()里填上合适的数1.2=1*22+4=6=2*32+4+6=12=3*42+4+6+8=20=4*52+4+6+8+10=( )=( )*( )2+4+6+……+98+100=( )=( )*( )……2+4+6+8+……+n=( )=( )*( )2.1/2=1/1*2=1-1/21/6=1/2*3=1/2-1/31/12=1/3*4=1/3-1/41/20=1/
2+4+6+8+10=(30)=( 5 )*( 6 )
2+4+6+……+98+100=( 2550 )=( 50 )*( 51 )……
2+4+6+8+……+n=( n*(n+2) /4 )=( n/2 )*( n/2 +1 )
2.1/2=1/1*2=1-1/2
1/6=1/2*3=1/2-1/3
1/12=1/3*4=1/3-1/4
1/20=1/( 4 )*( 5)=1/( 4 )-1/( 5 )
1/1*2+1/2*3+1/3*4+……+1/99*100=1-1/100=( 99/100 )
1. 2=1*2
2+4=6=2*3
2+4+6=12=3*4
2+4+6+8=20=4*5
2+4+6+8+10=(30)=(5)*(6)
2+4+6+……+98+100=(5050)=(50)*(51)……
2+4+6+8+……+n=(n^2/4+n/2)=(n/2)*(n/2+1)
2. 1/2=1/...
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1. 2=1*2
2+4=6=2*3
2+4+6=12=3*4
2+4+6+8=20=4*5
2+4+6+8+10=(30)=(5)*(6)
2+4+6+……+98+100=(5050)=(50)*(51)……
2+4+6+8+……+n=(n^2/4+n/2)=(n/2)*(n/2+1)
2. 1/2=1/1*2=1-1/2
1/6=1/2*3=1/2-1/3
1/12=1/3*4=1/3-1/4
1/20=1/(4)*(5)=1/(4)-1/(5)
1/1*2+1/2*3+1/3*4+……+1/99*100=(1-1/100=99/100)
收起
30,5×6
2550,50×51
(n/2)×(n/2+1),前一空把他乘一下
4×5,4,5
1-1/100=99/100