ABACUS – SUBTRACTION
The rules followed in abacus addition are applicable in subtraction too. The highest digit
in the smaller number should be subtracted from the corresponding digit of the higher
number and so on. The procedures are explained in the following problems.
A. Example : 43 - 32
a) Set the number 4 of the 43 in the tens column with right hand and set 3 of the
43 in the units column by moving hands to the right.
b) Like addition, subtraction is also done from left to right. In this example, we
have to subtract 3 from 4 in the tens column and 2 from 3 in the units column.
c) Place your right hand on the number 4 of the 43 and clear 3 beads.
d) Move both hands to the right, clear 2 beads in the units column.
e) Count the number in the abacus, the answer is 11. This is DIRECT subtraction.B. Example : 82 - 19
a) Set the number 8 of the 82 in the tens column.
b) Set the number 2 of the 82 in the units column. Now your right and left hands
should be on the units and tens column respectively.
c) In this example, we have to clear 1 in the tens column and 9 in the units
column.
d) Clear one bead in the tens column and move to the right to clear 9 in the units
column. Since the units column has only a value 2, it will not be possible to
clear 9 in that column.