GB2391999A

GB2391999A - Educational number device for addition and subtraction

Info

Publication number: GB2391999A
Application number: GB0218786A
Authority: GB
Inventors: Sumanasiri Wijesingh Ekanayake
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-08-13
Filing date: 2002-08-13
Publication date: 2004-02-18
Also published as: GB0218786D0

Abstract

An educational number device for performing addition and subtraction has both positive and negative numbers marked on it. The device may in the form of a linear ruler or a circular disc and may also be marked with arrows indicating positive and negative directions. The number ruler may be provided with a peg and holes for indicating numbers. Similarly the number circle may be provided with a rotatable pointer.

Description

! NUMBER RULER

AND NUMBER CIRCLE

Number Ruler and Number Circle are two mathematical equipments which can be used to illustrate and workout algebraic addition of numbers.

It is a difficult task to illustrate the concept of algebraic addition of numbers.

These two mathematical equipments can help school children to learn the concept of algebraic addition of numbers. School teachers would find it much easier to illustrate the concept of algebraic addition in classroom teaching.

Number Ruler has numbers marked from -I I to + 11 and each number has a hole next to it. More numbers can be marked according to the size and the scale of the ruler. A lcey is attached to one point of the ruler with a string or a cord and this key is used to locate and identify the number by placing it in the hole next to it.Two sets of arrows are drawn in opposite directions; one set is positive and other is negative.

Number Circle has numbers marked from -l 7 to i 17 around the circle. More numbers can be marked according to the size and scale. A pointer which is fixed at the centre can be turned in a clockwise or ant' clocl; wise direction. Two arrows are drawn; one in a clockwise direction, which is marked positive and the other arrow in a anticlockwise direction which is marked negative.

These features help straight forward location and identification of numbers giving a visual image of the mathematical operation.

! Figure I is the Number Ruler In figure 1 1 - negative arrows 2 positive arrows 3 - the key (to locate numbers) 4- positive numbers 5 negative numbers 6- holes (to identify numbers) 7- starting point How the Number Ruler works (Fig 1) Following examples of algebraic addition would illustrate how Member Ruler works E 5 - 3 -

Starting from zero move the lcey 5 holes in the positive direction and further 3 holes in positive direction and plant the key.You would end up in the hole next to 8.

The answer is 8.

F,x2 5 -3--2 Starting from zero move the key 5 holes in the positive direction and then move the 3 holes in the negative direction. The key would end up in the hole next to 2. The answer is 2.

F,x 3 -5 + 3 = -2 Starting from zero move the key 5 holes in the negative direction and 3 holes in the positive direction. The key will end up in the hole next to -2. The answer is -2.

Fix 4 -5 -3 =-8 Starting from zero move the key 5 holes in the negative direction and further 3 holes in the negative direction. The key will end up in the hole next to -8 The answer is -8.

Figure 2 is the Number Circle In figure 2 1-starting point 2- positive numbers 3- negative numbers 4- indicator (pointer) 5- stop point 6 positive arrow in clockwise direction 7- negative arrow in anticlockwise direction How the Number Circle works (fig 2) Exl 5+3=8 Starting from zero move the pointer 5 places in clockwise direction and further places in clockwise direction. Then the pointer will end up at number 8. The answer is8. F,x2 5-3=2 Starting from zero move the pointer 5 places in the clockwise direction and 3 places in the anticlockwise direction. The pointer will end up at number 2. The answer is 2.

Ex 3 -5 -3 =-2 Starting from zero move the pointer 5 places in the anticlockwise direction and then move the pointer 3 places in the clockwise direction. The pointer will end up at number-2. The answer is 2.

fix 4 -5-3 =-8 Starting from zero move the pointer 5 places in the anticlockwise direction and then move the pointer further 3 places in the anticlockwise direction. The pointer will end up at -8. The answer is -8.

Claims

f CLAIMS

NUMBER RULER

1. A number ruler which has positive and negative numbers marked on it.

2. A number ruler as claimed in Claim 1 where O is the starting point, and O

is marked at the centre of the ruler. Positive numbers are marked in one direction and negative numbers are marked in the other direction. More numbers can be added according to the length and the size of the ruler.

3. A number as claimed in Claim] and 2 where holes are made next to every number. 4. A number ruler as claimed in Claim I has a key fixed to the ruler with a string or cord which goes in holes to locate numbers.

5. A number ruler as claimed in Claim I, has two sets of arrows marked in both directions, one marked positive and the other marked negative.

6. A ruler as claimed in any proceeding claim, which is made from metal, plastic material, wood or from a combination of these materials 7. A number ruler substantially as herein described and illustrated in the accompanying drawings.

( CLAIMS

NUMBER CIRCLE

A number circle which has positive and negative numbers marked around the circumference of the circle.

1. A number circle as claimed in Claim 1 where zero is the starting point.

Positive numbers are marked to the right of zero. Negative number are marked to the left of zero. A stop point is marked at the finishing points of the numbers.

a, A number circle as claimed in Claim 1 has 2 arrows marked on the circle.

The clockwise arrow is marked positive and the anti-clockwise arrow is marked negative.

I A number circle as claimed in Claim 1 has a pointer, fixed at the centre, which can be turned in a clockwise and anti-clockwise direction.

L. A number circle as claimed in any proceeding claim is made from, metal, plastic material, wood or a combination of these materials.

i3. A number circle substantially as herein described and illustrated in accompanying drawings.