Number representation on the abacus
ABACUS is a simple calculating tool used to do all the basic arithmetic calculations like addition, subtraction, multiplication and division.
Abacus consist of rods in which beads move up and down.
A beam divides the abacus rod into two parts. The lower part has 4 beads known as the lower bead or earth bead. The upper part has one bead known as the upper bead or the heaven bead. Each lower bead has a value of “1” and each upper bead has a value of “5”. The beads are moved up and down the rods with the help of fingers. The thumb and the forefinger of our right hand and the forefinger and middle finger of our left hand are used to move the beads. There is a unit point (a white dot) marked at every 3rd rod on the abacus. This rod indicate the unit place value rod and the rods towards the left of this unit rod would be tens’ rod, hundreds’ rod, thousands’ rod etc. The rod on the right hand side of the unit rod would be used to represent the decimal place value digits.
Before using the abacus, it should be made sure that the value on each rods are in the neutral position representing “0”.
Abacus consist of rods in which beads move up and down.
A beam divides the abacus rod into two parts. The lower part has 4 beads known as the lower bead or earth bead. The upper part has one bead known as the upper bead or the heaven bead. Each lower bead has a value of “1” and each upper bead has a value of “5”. The beads are moved up and down the rods with the help of fingers. The thumb and the forefinger of our right hand and the forefinger and middle finger of our left hand are used to move the beads. There is a unit point (a white dot) marked at every 3rd rod on the abacus. This rod indicate the unit place value rod and the rods towards the left of this unit rod would be tens’ rod, hundreds’ rod, thousands’ rod etc. The rod on the right hand side of the unit rod would be used to represent the decimal place value digits.
Before using the abacus, it should be made sure that the value on each rods are in the neutral position representing “0”.
Abacus techniques
3. We always have to start counting from the bottom deck. Number one should be represented by moving one bead of one’s place towards the horizontal reckoning bar.
Similarly, by moving the beads towards the reckoning the bar we can make any number. As the bottom row has only four beads to make a number more than 4, we have to move back the bottom deck’s bead to its original position and bring down the heaven bead towards the reckoning bar. To make 6 with the heaven beads, you need one earth bead touching the reckoning bar. |
rEPRESENTATION OF 7 ON THE ABACUS
Now suppose we need to represent no. “7” on the abacus. So with the thumb finger of the right hand need to move two lower beads up and with the forefinger need to move one upper beads down.
REPRESENTATION OF 76 ON THE ABACUS
Representing no. “76” on the abacus. With the thumb of the right hand move one lower bead up on the unit rod and with forefinger move one upper bead down. Next in the tens’ rod with the left hand forefinger move two lower beads up and with the middle finger move one upper bead down.
REPRESENTATION OF 958 ON THE ABACUS
representing no. “958” on the abacus. With the thumb of the right hand move three lower beads up and with the forefinger move one upper bead down on the unit rod. Next with the middle finger of the left hand move one upper bead down in the tens’ rod. And lastly with the forefinger and the middle finger of the left hand move all the beads in the hundredth rod simultaneously towards the beam.
Adding and subtracting
- To add a number, let’s take 1234 with another number, we need to make the number 1234 first by moving the beads according to their place.
- Now we have to start adding from the left that is the highest place, in this case, it is the thousand place, and have to add 1 and 5. And gradually to the lower places.
- Since the tens place has carried over(3+7=10) so have to add one bead at a hundred’s place and moving the tens’ bead to its original place making the value zero. The same way has to add one’s place also.
- Now have to read from the left side, 1234+5678= 6912