"That the number of times you will have to go back into a store to retrieve items your children have left behind (x) is directly proportional to the number of children you brought with you (a), the number of items they brought in (b), and the number of stores you have visited (c), and also inversely proportional to the number of items you went into the store for in the first place (z). If the resulting figure is greater than 2, not all of the items will be retrievable.

Formula:

(a+b+c) /z = x"