Step-by-step explanation:
According to this description we need a number that can be divided by 2,3 and 4 since the amount of rocks can be described by a natural number. However if a number is divided by 4 it is divided by 2 as well since 2*2=4.
If α is a natural number then 2*α is a natural number as well as the product of two natural numbers.
Which means that we need a number devided by 3 and 4.
The smallest number that fulfills this demand is 3*4=12.
Also any product of 12 with any natural number can be devided by 3, 4 and 2.
If the exercise asks for the numbers that are divided only by 2,3 and 4 these are: