Fun fact: We actually learned algebra in elementary school, we just don't use the x value

I'm not sure in your case but did you do these kind of activities in math before?

  1. 3 + □ = 5
  2. □ - 8 = 10
  3. 9 + □ - 4 = 8

So that's basically algebra, just without the x value and replaced by a blank box instead