We all thought the tricks my 12 year old son was doing with these cards were great until my 8 year old son spoilt the fun by blurting out how it was done when he noticed the markings on the back. I do think the numbers could have been put on more subtlety, as the suit pictures are fairly well disguised. Unfortunately they will now be rendered useless, as my 12 year old does not want to ever suffer the humiliation of being discovered again and (as he said) if an 8 year old can spot it, then so would most people!! Great for doing tricks for grannies and very young children who are not so observant.