I saw the video on the website you gave, number 1 to 6 are right, but 7 to 9 are very weird. I can't understand if some one show that to me. 7 we usually use thumb and index finger, just like the number 8 in the website. 8 we usually add middle finger to 7. so we use three fingers to symbol the 8. 9 we usually add ring finger to 8. so we use four fingers to symbol the 9. BTW, the number 7 in the website, the thumb touch the index finger and the middle finger, it may let people think that you are asking for money.the number 9 in the website, you can use that but get more careful, you need to say 9 with this action because it is means dead usually.and the 8 in Chinese is a good number but is not means lucky. it's means "be rich" because its sound.

I'm not sure whether my answer is right or not. But in my conception of Chinese number counting,I‘d like to express these views: 六，the thumb can represent 5,and the pinky 1,then you can understand. 九，people think the shape of 9 is just like the shape of curving you index finger,and you can have a try :)other fingers can not mange it perfectly like your index finger 七，the strategy to count 7 differs in China.From my habit, the image of the webisite given by you is different.So I can't explain that.

谢谢你给我分享，Simple_Smile ^_^

but 7 & 8 in the website are not Chinese style I guess....and really confusing...

that is most common as it is easy to read.