US 856041 A
Description (OCR text may contain errors)
AUGUSTA D. DUNN, OF SANFORD, FLORIDA.
Specification of Letters Patent.
Patented. June 4, 1907.
Application filed January 31, 1907. Serial No. 355,030.
To all whom, 7125 may con/cern:
Be it known that I, AUGUSTA D. DUNN, of Sanford, in the county of Orange and State of Florida, have invented certain new and useful Improvements in Counting-Boards, and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.
Instructors in the primary school grades frequently find it necessary, in teaching the first principles of arithmetic, to give demonstrations of the carrying and borrowing in addition and subtraction, respectively, and for this purpose sometimes employ slivers of wood, marbles, buttons, and other small objects arranged in hundreds, tens and units, and tied in bundles or packages, which must be tied and untied for each lesson. Such articles become cumbersome when the problemsare of large denominations, and are generally unsatisfactory.
The object of my invention is to provide a simple and inexpensive counting device for impressing beginners, by means of tangible evidence, with the value of the number of units carrier in addition, and borrowec in subtraction. Y
The invention will be hereinafter fully set forth and particularly pointed out in the claims.
In the accompanying drawings, Figure 1 is a front elevation. Fig. 2 is a side view. Fig. 3 is a detail, showing one of the counting disks removed.
Referring to the drawings, 1 designates a base which is preferably of rectangular shape, whereon are three perpendicular rows of pegs 2, nine pegs constituting a row. The pegs may be secured to the board in any desired manner, and, preferably, project therefrom at an acute angle. The counters or disks 3 consist each of a square of pasteboard or other stiff material having a central aperture 4. These disks are designed to be slipped over the pegs, the angle thereof insuring their retention thereon, as against accidental displacement. Vhen the board is not in use each peg of the hundreds row holds'100 disks, the pegsof the tens row, ten disks each, and those of the units row, one each,
making in all nine hundred and ninety-nine disks. The pegs of each row are varied in length accordingly.
The use of the device will be understood from the following examples.
The addition of 126 and S7: The disks being removed from all pegs, the teacher places 100 disks on one peg in the hundreds row, 10 disks on each of two pegs in the tens row, and 1 disk on each of siX pegs in the units row. To the 6 units add the 7 units of the 87. Thus there are thirteen units, 10 lof which, (representing the carrying figure) are placed on one peg in the tens row, leaving 3 disks in the units row. Three of the pegs of the tens row each contain 10 disks, to which are to be added 8 tens, making in all 11 tens, of which 10 tens, or 1 hundred, are carried, and leaving 1 ten,7 (10 disks) in the tens row. The board will now show 2 hundreds, 1 ten, and 3 units, in all 213 disks.
The subtraction of 87 from 126: The disks are placed as before to represent 126. There being but 6 units 7 cannot be taken therefrom. It is necessary, therefore, to borrow 1 ten (10 disks), making 16 units in the units row. Taking away the 7 units of the subtrahend, 9 units are left in the units row. But 1 ten appears on the board in the tens row, from which 8 are to be taken. 1 hundred (100 disks) is bor-v rowed from the hundreds row, making 11 tens (110 disks). After taking off S tens (80 disks) 8 tens remain (30 disks),
which with the 9 disks in the units row give the remainder 39.
In adding more than two numbers, for instance, 27 plus 45 plus 16 plus 9, the numbers are written on the blackboard, the beginners take the disks and count off the various units, 7, 5, 6, 9, making in all 27 units. From these 27 disks they take the 2 tens (20 disks), leaving 7 disks in the units row, one disk on each of seven pegs. The 2 tens are placed on pegs in the "tens row and to these are added the 2 tens of the 27, 4 tens of the 45, and 1 ten of the 16, in all 9 tens The result is 9 "tens and 7 units97.
It will be seen that a counting device constructed and operated in accordance with my invention is easily handled, and is productive of highly efiicient results.
I claim as my invention:
1. An arithmetical device comprising an approximately vertically ldisposed base, a plurality of rows of pegs projecting forwardly IOO IIO
therefrom on a slightly inclined plane, each row representing a different value, and removable members designed to be held by said pegs, the number of such members for each 5 peg of each row corresponding to the value of the respective row of pegs.
2. An arithmetical device comprising a base having a plurality of rows of holding devices, each row being composed of nine ro such devices, and each row of a different value from the others, and removable memi bers designed to be held by said holding f devices, the number of such members for each holding device of each row correspond- IE5 ing to the value of the respective row of holding devices.
specification in the presence of two subscribing witnesses.
AUGUSTA D. DUN N l Witnesses:
B. F. WHITNER, Jr., F. I. WAITE.