a note on long division

1
A NOTE ON LONG DIVISION HAROLD D. LARSEN The University of New Mexico, Albuquerque, New Mexico The process of long division is usually considered to be one of the most difficult operations in arithmetic. Much of this difficulty is due to the in- sistence on finding the correct quotient figure before proceeding with the division. This frequently requires two or more trials and the consequent erasures of the discarded products. Elaborate rules have been formulated to aid in determining the correct quotient figure, all of which require con- siderable mental computation. As a matter of fact, the difficulty of long division has been exaggerated. The whole process is very much simplified if an incorrect product is not erased. If the subtraction of the trial product is actually carried out, the remainder can be used very conveniently to adjust the incorrect quotient figure. I have examined a large number of text-books on arithmetic, but have failed to find any discussion of such adjustments. The following examples illustrate simple methods for adjusting trial quotients. Two cases arise, depending on whether the trial quotient is too small or too large. Example 1. Explanation. The trial quotient 7 yields a re- 8 mainder 648, and hence is too small. Instead of 71 erasing the trial product and starting over, it is more convenient to change the quotient 582)47223 figure to 8 by subtracting an additional 582 from 4074 648. 648 582 663 582 __ ^ 81 Example 2. Explanation. The trial quotient 8 is too large, 7 since the trial product exceeds the dividend by ^6 118. Change the quotient figure to 7 by adding 368to-118. 368)28265 2944 -118 368 2505 2208 297 If your journal does not reach you notify Ray C. Soliday, P.O. Box 408, Oak Park, Illinois. 578

Upload: harold-d-lassen

Post on 30-Sep-2016

212 views

Category:

Documents


0 download

TRANSCRIPT

A NOTE ON LONG DIVISION

HAROLD D. LARSENThe University of New Mexico, Albuquerque, New Mexico

The process of long division is usually considered to be one of the mostdifficult operations in arithmetic. Much of this difficulty is due to the in-sistence on finding the correct quotient figure before proceeding with thedivision. This frequently requires two or more trials and the consequenterasures of the discarded products. Elaborate rules have been formulatedto aid in determining the correct quotient figure, all of which require con-siderable mental computation.As a matter of fact, the difficulty of long division has been exaggerated.

The whole process is very much simplified if an incorrect product is noterased. If the subtraction of the trial product is actually carried out, theremainder can be used very conveniently to adjust the incorrect quotientfigure. I have examined a large number of text-books on arithmetic, buthave failed to find any discussion of such adjustments.The following examples illustrate simple methods for adjusting trial

quotients. Two cases arise, depending on whether the trial quotient is toosmall or too large.Example 1. Explanation. The trial quotient 7 yields a re-

8 mainder 648, and hence is too small. Instead of71 erasing the trial product and starting over, it

��� is more convenient to change the quotient582)47223 figure to 8 by subtracting an additional 582 from

4074 648.

648582

663582__ ^81

Example 2. Explanation. The trial quotient 8 is too large,7 since the trial product exceeds the dividend by^6 118. Change the quotient figure to 7 by adding

��� 368to-118.368)28265

2944

-118368

25052208

297

If your journal does not reach you notify Ray C. Soliday, P.O. Box 408,Oak Park, Illinois.

578