________a_______b_____c_____d_____e_____f_________g____ Kể tên: ab,ac,bc,bd,cd,ce,de,df,ef,eg,fg,ag,bg, … Bình luận
________a_______b_____c_____d_____e_____f_________g____
Kể tên: ab,ac,bc,bd,cd,ce,de,df,ef,eg,fg,ag,bg,
…
$Trong$ $hình$
Xin $ctlhh$