1/4+(2+1/10)+(4+1/18)+(6+1/28)+(8+1/40)+(10+1/54)=?
找规律填空.(1)2,6,18,54,(),(),(2)1,2,4,6,7,10,10,14,(),().(3)1,3,
计算: 1/2×4+1/4×6+1/6×8+1/8×10+1/10×12
2/1-4/1)+(4/1-6/1)+(6/1-8/1)+(8/1-10/1).+(48/1-50/1)=?/
1/2*4+1/4*6+1/6*8+1/8*10+---+1/198*200
1/2+1/4+1/6+1/8+1/10+1/12+1/14+1/16+1/18+1/20的计算结果和简便计算方式
1/(2*4)+1/(4*6)+1/(6*8)+1/(8*10)+……1/(48*50)=?
10/1*2*3*4+18/3*4*5*6+26/5*6*7*8=
1/(1*3)+1/(2*4)+1/(3*5)+1/(4*6)+...+1/(8*10)=?
2/1 3/1 4/1 5/1 6/1 8/1 10/1 12/1 15/1 20/1
已知18+4+16+20=4 9+13+8+2=3 6+28+10+1=4 问7+16+20=?多少
y=4x:4;8;12;16;20;24;28;32;36;40y=10-x:9;8;7;6;5;4;3;2;1;0.
1/2*4+1/4*6+1/6*8+1/8*10+1/10*12.+1/2010*2012