That's pretty much exactly how you first learn to do arithmetic. Break the (whole) numbers down into their smallest (whole) part and count em up. That's what number lines do, or using colored blocks to visually do the addition, or any number of other techniques you use when you're first learning arithmetic. I mean, even just knowing 3 + 3 = 6 is memorization, a shortcut form of 1 + 1 + 1 + 1 + 1 + 1 = 6.