If the Roman Empire is really so far removed from us in time,
why is it that Roman numerals were still in commercial use until
the 14th century? Before we throw our own guess into the debate,
let us look at the nature of these much maligned numerals. How
could anyone calculate with them? Well, how can anyone compute
"three hundred and seventy-six times two hundred and thirty-
seven". You type these data into you pocket calculator and press
the "x" button, that's how. You certainly would not fill page
after page with number words. Neither did the Romans: they would
load CCCLXXVI and CCXXXVII onto their counting board or abacus
and manipulate the pebbles and beads until they had the result.
We shall presently do such a multiplication, but first we'll
look at addition and subtraction. The counting board shown here
is divided into two vertical strips, the right hand one for
addition, the other for subtraction. The top number shown on the
right is MDCCCCLXV, the lower one is MCCCCXXV. To add them, we
just pile ever