Thought I'd check the arithmetic for 2 two-digit numbers, and it works!<p>I expect 41+14 to be 12 (two right plus two up equals two right and two up).<p>Long addition in long form below uses:<p>'=' to show equivalent lines (reordering of terms (1+2=2+1), spliting numbers (41=40+1), adding single digits (1+4=22))<p>'->' for when the algorithm gives a digit<p>'<' for when we move over a column<p><pre><code> 41+14
= (40+1)+(10+4)
= 40 + 10 + (1+4)
= 40 + 10 + 22
-> 1s digit = 2
< 4 + 1 + 2
= 22 + 2
= 20 + 2 + 2
= 20 + 41
-> 10s digit = 1
< 2 + 4
= 0
-> done
== 12
</code></pre>
[edit] Just noticed the article has two different numbering systems, one where 10, 20, 30, 40 are clockwise and one where they are anticlockwise. In both, 1, 2, 3, 4 are clockwise. My addition is on the second, where 10s are anticlockwise (this is what is used in the addition table).<p>It still works in the alternative system (14+21 should equal 12)<p><pre><code> 14+21
=10+20+42
->2
<1+2+4
=13+4
=10+3+4
=10+31
->1
<1+3
=0
==12</code></pre>