数一数，图2-1和图2-2中各有多少黑方块和白方块?/@+];r2I4['?9s+a'\5{.l1b)X
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仔细观察图2-1，可发现黑方块和白方块9I.u'D1|4Z0R多.因为每一行中有6y0S5w)_(a2_/r2Z0I9W个黑方块和4b-z*l6t.l9J6h3r8_0K2p'R)`1[个白方块，共有'W'@1D3z;~4p4S'k+n行。由于白方块比黑方块多1个，所以白方块是,U*[3R;L;H个，黑方块是4@;^-L:A6@9_,P;l5Y7Q6`5q.w;W(Y.~:_个./@+];r2I4['?9s+a'\5{.l1b)X