2 2 - Two and two added together make 4 1 - One and four together make 5 2 - Five and two together make 7 1 - Seven and one together make 8 2 - What are eight and two? They make 10 10 - Twice ten make 20 5 - Twenty is a score, and five score 100 [Illustration: Battledore, "Lessons in Numbers"] Many scholars never saw a printed arithmetic; and when the master had one for circulation it was scarcely more helpful than the sum-book. One of the most ancient arithmetics was written by the mathematician Record, who lived from the year 1500 to 1558. He is said to have invented the sign of equality =, but there is nothing in his book to indicate this fact. The terms "arsemetrick" and "augrime" are used in it, instead of arithmetic. Many curious and obsolete rules are given, among them, "The Golden Rule," "Rule of Falsehood," "The Redeeming of Pawnes of Geams," "The Backer Rule of Thirds." Here is a simple problem under the latter:-- "I did lend my friend 3/4 of a Porteguise 7 months upon promise that he should do as much for me again, and when I should borrow of him, he could lend me but 5/12 of a Porteguese, now I demand how long time I must keep his money in just Recompence of my loan, accounting 13 months in the year." Rhyme is used in this book, in dialogues between the master and scholar. Copies of _Cocker's Arithmetick_ are said to be very rare in England, but I have seen several in America. An edition was published in Philadelphia in 1779. The frontispiece of English and American editions shows the picture of the mathematician surrounded by a wreath of laurel with the droll apostrophe:-- "Ingenious Cocker! Now to Rest thou 'rt Gone Noe Art can Show thee fully but thine Own Thy rare _Arithmetick_ alone can show What vast Sums of Thanks wee for Thy Labour owe."