In arithmetic, the galley method, also known as the batello or the scratch method, was the most widely used method of division in use prior to 1600. The names galea and batello refer to a boat which the outline of the work was thought to resemble. An earlier version of this method was used as early as 825 by Al-Khwarizmi. The galley method is thought to be of Arab origin and is most effective when used on a sand abacus. However, Lam Lay Yong's research pointed out that the galley method of division originated in the 1st century AD in ancient China. The galley method writes fewer figures than long division, and results in interesting shapes and pictures as it expands both above and below the initial lines. It was the preferred method of division for seventeen centuries, far longer than long division's four centuries. Examples of the galley method appear in the 1702 British-American cyphering book written by Thomas Prust (or Priest). How it works Set up the problem by writing the dividend and then a bar. The quotient will be written after the bar. Steps: (a1) Write the divisor below the dividend. Align the divisor so that its leftmost digit is directly below the dividend's leftmost digit (if the divisor is 594, for instance, it would be written an additional space to the right, so that the "5" would appear below the "6", as shown in the illustration). (a2) Dividing 652 by 594 yields the quotient 1 which is written to the right of the bar. Now multiply each digit of the divisor by the new digit of the quotient and subtract the result from the left-hand segment of the dividend. Where the subtrahend and the dividend segment differ, cross out the dividend digit and write if necessary the subtrahend digit and next vertical empty space. Cross out the divisor digit used. (b) Compute 6 − 5×1 = 1. Cross out the 6 of the dividend and above it write a 1. Cross out the 5 of the divisor. The resulting dividend is now read off as the topmost un-crossed digits: 15284. (c) Using the left-hand segment of the resulting dividend we get 15 − 9×1 = 6. Cross out the 1 and 5 and write 6 above. Cross out the 9. The resulting dividend is 6284. (d) Compute 62 − 4×1 = 58. Cross out the 6