Final answer:
The question seems to be an incorrectly written algebraic expression, but answers were provided focusing on the principle of canceling identical units in a fraction during dimensional analysis or unit conversion.
Step-by-step explanation:
The student's question appears to be a typo or a miswritten algebraic equation. Despite the unclear initial question, the examples provided relate to the principle of canceling units in a fraction when they appear in both the numerator and the denominator. In unit conversions or equations, when the same unit is present in both the top and bottom, they cancel out, simplifying the expression. As for the mathematical expressions provided, the examples given, such as 3.55 m being simplified to 355 cm and the unit conversion concept applied to ratios like 1/20 = 1/5.5, illustrate how to deal with units in calculations. These are basic principles in dimensional analysis, which is often taught in high school physics and chemistry courses as well as in mathematics.