I think parent wondered how it&#x27;s possible that she remembered 16+16=32.<p>Children raised on positional decimal arithmetic are &quot;supposed&quot; to figure that 10+10=20 or 20+20=40 and then add&#x2F;subtract 5+5.<p>Of course it&#x27;s easier to associate 15 with 16 than with 10 or 20, but the fact that she immediately knew 2·16 and was able to proceed further says something about either her experience with binary arithmetic or some tendency to spontaneously count in binary.