denominator exceeds three digits, move the placement of the respective divisions
according to your interest. You must note that the calculations do not run into
one another.
II. ADDITION OF FRACTIONS :
Example : 567 +^745
a) Calculate the common denominator for the fractions. The denominator of 76 is
7 and 54 is 5. For 7 and 5, 35 is the least common denominator.
b) Set the denominator (common) in the extreme right of the abacus. The unit digit
of the number should always be set in the extreme right of the particular section.
That is, place the 3 of the common denominator in the tens column and the 5 in
the units column.
c) What is the whole number of the first fraction 5 76? It is 5. Set five in the
appropriate column. That is, set the number in the section meant for whole
number, i.e, in the 7th column from the extreme right side of the abacus. With this
add the whole number of the second fraction, that is, you have to add 7 with 5,
making the whole number into 12.
d) Now take the fraction part of the first number. It is 76. Set the numerator 6 in the
extreme left of the abacus. Now skip one column to the right of it and set the
denominator 7. There is no need to set the number in the abacus if you are able to
remember the same. However, it is usually preferred to set the number for the
purpose of reference.
e) By keeping your left hand on the 7 and right hand on the common denominator
35, ask : how many 7’s in 35? By saying 5, you clear the 7 and set 5. With this 5,
multiply the numerator 6. By saying 6×5 = 30, you have to set the 30 in the
section meant for the numerator. That is, the 0 of the 30 should be set in the
fourth column and 3 in the fifth column from the extreme right of the abacus.
