"The 'IV' form is late," said the puzzle-maker. "I show you something. Copy column of pocket cash-book in Roman numerals, then, without thinking in figures, add up column."
Not in the least understanding what were the old man's ideas the boy did as he was told. It was easy enough to write down the numbers, but when he came to add them up, he found himself thinking of Arabic figures in spite of himself.
"I'm cheating," said Eric suddenly, "I can't help adding up in the old way."
"Good boy," said the puzzle-maker. "I knew that. I show you some more. Simple addition. Write in Roman numerals one billion, seven hundred and forty-two million, nine hundred and eighty-three thousand, four hundred and twenty-seven and eleven-sixteenths."
Although pretty well posted, Eric had a hard time writing down the number and had to ask a lot of questions before he could even write it correctly. Then the puzzle-maker gave him half a dozen figures of the same kind. It looked weird on paper.
"Now add him up," the old man charged him.
The boy started bravely. But he hadn't gone very far before he got absolutely stuck. He wrestled with that sum of simple addition for nearly an hour. At last he got a result which seemed right.
"Put him down in ordinary figures," came the order. "Add him up."
Eric did so, having his own difficulties in re-transcribing from the Roman numerals.
"Are they the same?"