A] X-1,25x4= 2,5 b] [ X CONG 1 ] CONG [ X CONG 2] CONG [ X CONG 3 CONG ] .............. CONG [ X CONG 20] = 750 C ] [ X CONG 1] CONG [X CONG 2 ] CONG [ X CONG 3 ] CONG ........... CONG [ X CONG 10] = 175
[ 2 CONG X ] CONG [ 4 CONG X ] CONG [ 6 CONG X ] CONG .......................... CONG [ 52 CONG X ] = 780
[ X 1 cong ] cong [ X 2 cong ] cong[ X3 cong] CONG .............. CONG 20 = 750
1 CONG 3 CONG 5 CONG .........CONG [ 2 x X CONG 1] = 169
2 CONG 4 CONG 6 CONG ........... CONG [ 2 x X] = 2550
x cong 1 cong x cong 2 cong ...x cong 100 bang 5050
1 CONG 3 CONG 5 CONG CONG .......... CONG [ 2x X CONG 1] =169
1 CONG 3 CONG 5 CONG ............... CONG [ 2x X 1] CONG 169
3 phan 1 nhan 4 cong 3 phan 4 nhan 7 cong 3 phan 7 nhan 10 cong ... cong 3 phan 40 nhan 43