"Guess, what's the number?" Yesterday morning, Huangjueping Farmers' Market in Jiulongpo District. Ms. Chen, who sells vegetables here, held up a poker card of 5 diamonds, and used her fingers to cover the number 5, asking a little girl to guess the number. "Five." The little girl blurted out. "Wow! You really guessed it!" Ms. Chen exclaimed. Then she took another one...