Statisticians call the pattern behind these counts the hypergeometric distribution: numbers taken from a pool without putting any back. It gives the probability of hitting exactly three, four or five of the drawn numbers, and the lottery winning probability table in the game rules is that distribution written out. The probability of winning a prize of any size is the sum of those rows, and the math is exact, with nothing left to guess.
Lottery odds are calculated with one formula from school math: the number of ways to choose some numbers from a pool. Six numbers from forty nine give nearly fourteen million combinations, so the odds of the top prize are about one in fourteen million. A game drawing five from seventy, with one extra ball from a second pool of twenty five, multiplies two such counts and lands near three hundred million. Every number added to the pool raises the count steeply.
What is lottery odds for one person holding one ticket? The same number as for everyone else. Your chances of winning the lottery do not grow with loyalty, with a lucky shop or with years of play, because each draw starts fresh. The honest answer to what my odds are is printed in the game rules: one chance for every combination bought, against the full count of combinations the draw permits.