Eratosthenes of Cyrene was a 3rd century BCE mathematician from ancient Greece interested in prime numbers, that is numbers only divisible by 1 and themselves.
Cyrene 的埃拉托色尼 (Eratosthenes of Cyrene) 是公元前 3 世纪来自古希腊的数学家,他对素数很感兴,素数只能被 1 和它们本身整除。
Because it means that one of the possible values for the total amount of fish must be divisible by one of the possible values for the total amount of tanks.