1 dice toss has a 1 in 6 chance of showing 1 dot 1/6

tossing 2 dice... both resulting in 1 is 1/6 * 1/6 or 1/36 - one out of 36 throws on average...

So 1/100 * 5/1000 would be 5/100000 or 5 out of every 100000 situations where both scenarios exists... Vas and tubes tied as couple exists.

That's my take...