Presentation of the soroban - Representation of numbers
The Soroban is made of beads that we can move vertically on metal or wooden rods. Here is a representation of the Soroban:
The top beads are called Five Beads because they are counted by 5. The bottom beads are called One Beads because they are each counted by 1.
The initial position as shown above represents the number 0.
To activate a bead, then it must be moved to the side of the bar. The following situation represents the number 1 because a One Bead is moved to the side of the bar:
To represent the number 2, then you need to put 2 One Beads on the side of the bar:
So, to represent the number 3, you have to put 3 One Beads on the side of the bar and to represent the number 4, you have to put 4 One Beads on the side of the bar.
And to represent the number 5, you have to put the Five Bead on the side of the bar, putting the 4 One Beads back to their original place:
You can now guess that to represent the number 6, you need to activate the Five Bead and a One Bead:
5 + 1 = 6
By using the first column, the one furthest to the right, we can represent up to the number 9:
Remember the following operations and representations:
| 6 = 5 + 1 | 7 = 5 + 2 | 8 = 5 + 3 | 9 = 5 + 4 |
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Representation of numbers greater than 9
To represent numbers greater than 9, we use the other columns. The second column in orange is called the tens column. The third column in blue is called the hundreds column. And so on...
In the tens column :
- A One Bead is counted by 10 or a ten.
- A Five Bead is counted by 50 or 5 tens.
For example, let's take the number 23:
- We have 3 units, so we must represent 3 in the units column.
- And we have 2 tens, so we must represent 2 in the tens column.
The representation of the number 23 on the soroban is thus :
Another example the number 67 :
In column of hundreds :
- A One Bead is counted by 100 or a hundred
- A Five Bead is counted by 500 or 5 hundreds.
For example, let's take the number 264. The representation on the soroban is as follows:
Another example the number 782 :
1st exercise
In the first exercise you will have a sequence of numbers to represent on the virtual soroban. You can also work with a real soroban if you have one. Click on the following button to start:
2nd exercise
In the second exercise you will have a sequence of numbers to represent on the virtual soroban. You have to read the number corresponding to each representation. Click on the following button to start: