"Francesca," I said, "you wrong me. I'm a great deal of good. Of course I don't pretend to be able to run three fingers up three columns of figures a yard long and to write down the result as £7,956 17s. 8d., or whatever it may be, without a moment's pause. I can't do that, but for the ordinary rough-and-tumble work of domestic addition I'm hard to beat. Only if I'm to do these books of yours there must be perfect silence in the room. I mustn't be talked to while I'm wrestling with the nineteens and the seventeens in the shilling column."
"In fact," said Francesca, "you ought to be a deaf adder."
"Francesca," I said, "how could you? Give me the butcher's book and let there be no more jeux de mots between us."
I took the book, which was a masterpiece of illegibility, and added it up with my usual grace and felicity.
"Francesca," I said as I finished my task, "my total differs from the butcher's, but the difference is in his favour, not in mine. He seems to have imparted variety to his calculations by considering that it took twenty pence to make a shilling, which is a generous error. Now let me deal with the baker while you tackle the grocer, and then we'll wind up by doing the washing-book together."
The washing-book was a teaser, the items being apparently entered in Chaldee, but we stumbled through it at last.
"And now," I said, "we can take up the subject of thrift."
"I don't want to talk about it," she said, "I'm thoroughly tired of it. We've talked too much about it already."
"You're wrong there; we haven't talked half enough. If we had, the books wouldn't have gone up."
"They haven't gone up," she said. "They're about the same, but we've been having less."