There is no difference between the two, the number of "one" (can only be used alone, can not constitute a synthetic numeral, can not take quantifiers, used to refer to a point in dice and dominoes, but now it is also used instead of "one" when talking about numbers). Such as Yaoyaosan (1 13). Another mahjong term, Yao Wan, Yao Tiao, Yao Bing, Yao Ji, Yao Xi and Yao Pai.

It is generally recognized that "1" and "7" are similar in pronunciation in noisy environment, so "1" is pronounced as "Yao Yao" and "7" is pronounced as "turn".