设最底层7块砖上的数字依次为
G1 G2 G3 G4 G5 G6 G7
则第二层（从下向上数）的6块砖上的数字为
F1 F2 F3 F4 F5 F6
则
F1 = (G1 + G2)/2
F2 = (G2 + G3)/2
F3 = (G3 + G4)/2
F4 = (G4 + G5)/2
F5 = (G5 + G6)/2
F6 = (G6 + G7)/2
第三层5块砖上的数字为
E1 = (F1+F2)/2 = (G1 + 2G2 + G3)/4
E2 = (F2+F3)/2 = (G2 + 2G3 + G4)/4
E3 = (F3+F4)/2 = (G3 + 2G4 + G5)/4
E4 = (F4+F5)/2 = (G4 + 2G5 + G6)/4
E5 = (F5+F6)/2 = (G5 + 2G6 + G7)/4
第四层上的四块砖为
D1 = (E1+E2)/2 = (G1 + 3G2 + 3G3 + G4)/8
D2 = (E2+E3)/2 = (G2 + 3G3 + 3G4 + G5)/8
D3 = (E3+E4)/2 = (G3 + 3G4 + 3G5 + G6)/8
D4 = (E4+E5)/2 = (G4 + 3G5 + 3G6 + G7)/8
如此类推下去,最顶层为
A = (G1+6G2+15G3+20G4+15G5+6G6+G7)/64
若使 A 最小.则
G4 = 0
G3 、G5 = 1 、2
G2 、G6 = 3 、4
G1 、G7 = 5 、6
A = ( 5 + 6*3 + 15*1 + 20*0 + 15*2 + 6*4 + 6)/64 = 98/64 = 49/32
若使 A 最大.则 把大数放最底层中间,小数放两边
A = (0 + 6*2 + 15*4 + 20*6 + 15*5 + 6*3 + 1)/64 = 286/64 = 143/32
