Remark 3.4.2.
In the last example, itβs important to identify which fraction bar is the βmainβ fraction bar, and which fractions are βinternal.β Comparing the two expressions below, both of which are βone over two over threeβ, we see that they are not equivalent.
\begin{align*}
\frac{\ \frac{1}{2}\ }{3}\amp=\frac{\ \frac{1}{\cancelhighlight{2}}\ }{3}\multiplyright{\frac{\cancelhighlight{2}}{2}}\amp\amp\text{versus}\amp\frac{\ 1\ }{\frac{2}{3}}\amp=\frac{\ 1\ }{\frac{2}{\cancelhighlight{3}}}\multiplyright{\frac{3}{\cancelhighlight{3}}}\\
\amp=\frac{1}{6}\amp\amp\amp\amp=\frac{3}{2}
\end{align*}
For the first of these, the βmainβ fraction bar is above the \(3\text{,}\) but for the second of these, the βmainβ fraction bar is above the \(\frac{2}{3}\text{.}\)
