The kids’ shoes lay
Quiet on the stairs
Poised to trip they
Who walked there unawares

The kids’ mom swears
They will rue the day
As her ankle tears
Not much more to say

(Except perhaps their prayers.)

S’ is what happens when you’re making a plural noun – a noun that ends in s – possessive. Notice the difference in the poem’s two examples:

  1. kids’ shoes
  2. kids’ mom

See how the word “kids” takes the apostrophe after the s in both cases? In the first example, there are multiple things belonging to the kids…. their shoes. In the second example, there’s one thing (person) belonging to the kids… their mom. Regardless of whether or not the possessed item is singular or plural – in this case, mom or shoes – the apostrophe applied to the possessors – in this case, the kids – remains the same.

Kids’ = belonging to the children.