Accuracy should be first considered, then rapidity.

How to become a Lightning Calculator by Anonymous is part of the HackerNoon Books Series. Read this book online for free on HackerNoon!

Much of the information here contained is compiled from W. D. Rowland’s valuable little volume, entitled “How to become expert with figures.”

The time for such payment is called the equated time.

The time in bank discount is always the number of days from the date of discounting to the date of maturity.

Accuracy and rapidity in counting out change can best be acquired by practice behind the counter or at the cash-desk.

The unitate of a number is the sum of its digits reduced to a unit.

This rule of computing interest appears in some Canadian text-books, and, though simply a modification of other rules, is worthy of notice.

The transposition of figures is a frequent cause of errors in proving accounts and balance sheets.

In some respects this rule is superior to the well-known 60-day method of reckoning interest.

Require the interest of $462.50 for one month and eighteen days at 6 per cent.