按下面摆法摆80个三角形，有多少个白色的？0t:L1L3f1H2z(B9q
▲▲△△▲△▲▲△△▲△▲▲……0t:L1L3f1H2z(B9q
算式：提示+p6J6g-c-O6N(D;a8a0t:L1L3f1H2z(B9q
答：有-}-W/A-S7E*u/G+B*n个白色的三角形。0t:L1L3f1H2z(B9q