[A] Three days’ interest upon “cheques” paid to credit. 756 × 3. Now everything should be as clear as the flowing brook to Mr. Jones. He should, in the first instance rule a sheet of paper in exactly the same manner as the specimen page of the banker’s ledger. He next carries the entries from his pass-book to the ruled sheet, taking care that each amount, whether debit or credit, is placed under its right date, and at the end of each day, or when the next date appears, he extends the balance, as in our illustration, for it is upon this balance that the bank either allows or charges him interest for one, two, or twenty days, as the case may be, at an agreed rate. He then multiplies this balance by the number of days, and carries the product into a “total” column, which he adds up at the end of the half-year. This done, the rest is a very simple business for anybody who can manage a rule-of-three sum. The banker, we can see, brings forward the amount of Mr. Jones’ indebtedness on the 31st December when his books were ruled off. This opening entry, which amounts to £500 2s. 6d., is placed in the debit column of his ledger, and extended as a debit balance. Upon the morning of the 1st January, therefore, one day’s interest was owing on £500, but the next operation upon the account did not take place until 20th January; and as from 31st December (excluding the 31st and counting 1st January as one day) to 20th January (inclusive) there are twenty days, the customer owes twenty days’ interest upon £500. If we multiply 500 by 20, as in our form, and carry the product into “total” column, he then owes one day’s interest upon £10,000. The result, of course, is precisely the same; so a banker, in order to save a multiplicity of calculation, adopts this rule throughout, with the result that, at the end of the half-year, his client owes one day’s interest upon £37,422. Bankers, when referring to the figures in the “total” columns, speak of them mysteriously as “decimals,” and the customer, upon hearing so ominous a word, jumps to the conclusion that bankers’ calculations are most difficult and involved, when, in reality, they are of the simplest nature imaginable. Evidently the product in question is the result of a simple multiplication sum; so why bankers should speak of extending the “decimals,” when there is none to be extended, must ever remain one of the enigmas of their trade. As a rule, should the shillings in the balance column be ten or over, the banker, in making his calculations, calls them one pound, and when less than ten shillings he ignores them. On the 20th January, for instance, the shillings are excluded, but upon the 26th May £47 is the sum we have to multiply by five. Further, in arriving at the number of days between two dates, exclude the first date and include the second, or vice versa, but do not include both dates.