What is the probability of birthday coincidence is a math problem.

The probability of two people in the same Amanome is 1-364/365≈0.3%.

The probability that at least two people have the same birthday is 1-364/365*363/365≈0.8%.

Ten people, the probability that at least two people have the same birthday is1-364/365 * 363/365 * ... * 346/365 ≈1.7%.

Twenty people, the probability that at least two people have the same birthday is1-364/365 * 363/365 * ... * 336/365 ≈ 41.2%.

Thirty people, at least two people have the same birthday. The probability is1-364/365 * 363/365 * ... * 326/365 ≈ 60.6%.

Forty people, the probability that at least two people have the same birthday is1-364/365 * 363/365 * ... * 316/365 ≈ 89.1%.

Fifty people, the probability that at least two people have the same birthday is1-364/365 * 363/365 * ... * 306/365 ≈ 97.1%.

Sixty people, at least two people have the same birthday. The probability is1-364/365 * 363/365 * ... * 296/365 ≈ 99.4%.

There are 70 people, and the probability that at least two people have the same birthday is1-364/365 * 363/365 * ... * 286/365 ≈ 99.9%.

All probability teachers will probably talk about this problem.