d) What have you done in the previous step? Instead of adding 3, you have added
- Therefore, the excess 2 must be subtracted. Clear two beads of the units
column (in the lower abacus). Now the remaining value is 7, which is the
required answer.
III. ADDITION OF TWO DIGIT NUMBERS :
In addition, the higher value digits are always added first. The units column digits
will come at last.
Example : 37+36
a) Set the number 37 in the extreme right of the abacus. In setting and clearing
beads, we must be very careful in moving hands. That is, set the number 3 of
the 37 in the tens column with the right hand and set the number 7 of the 37 in
the units column with the same hand after setting number 3. Left hand rests on
the 3 in the tens column while the right hand is on the units column.
b) We are going to add 36 with 37. That is, we have to add 3 in the tens column
and 6 in the units column.
c) Since there is no 3 to add in tens column in the lower abacus, we can add 5.
d) Instead of adding 3, we have added 5.
e) Subtract the excess 2 in the tens column.
f) Next, we have to add 6 in the units column. There is no 6 to add in the units
column. Only two beads are remaining in the lower abacus.
g) Therefore, we shall go to the tens column. That is, set a bead in the tens
column. It means you have added 10 instead of 6. Therefore, subtract the
complement 4 from the units column.
h) Since there is no 4 to clear in the lower abacus in the units column, clear 5 of
the upper abacus and add 1 bead in the units column in the lower abacus.
i) Count the number in the abacus. The answer is 73.
