To simplify the expression, we can first find a common denominator for all the fractions. The common denominator will be the product of all the denominators:

1.3 * 2.4 * 3.5 * ... * 97.99 * 98.100 * 99

Next, we can multiply each fraction by the appropriate factor to get the common denominator:

(1/1.3) * (2.4/2.4) * (3.5/3.5) * ... * (97.99/97.99) * (98.100/98.100) * (99/99)

Simplifying each fraction, we get:

1 * 1 * 1 * ... * 1 * 1 * (49/99)

Since all the numerators are 1, we can ignore them. The expression simplifies to:

49/99

Therefore, the sum of the given expression is 49/99.