Way back in the day, we didn’t have base systems! It was uphill both ways, through the snow and blazing heat. When you wanted to count one, you’d write:

|

When you wanted 5, you’d write

|||||

And clearly, 1 + 5 = 6

| + ||||| = ||||||

This is the simplest way of counting.

The value of any number = number of |’s