I went to the ARRL's band plan site at https://clatsopauxcomm.org/index.php/technical/arrl-band-plan, and the first table began with the 60-metre band, which starts at 1.8MHz and ends at 2.0MHz. However, the next table shows the 80-metre band, which is 3.5 to 4.0MHz. This doesn't make sense. Shouldn't the wavelengths get shorter as frequencies increase?
It is simply an error or typo on that website. Take a look at the companion color chart on that page that is provided by the ARRL. It shows that frequency range as 160 meters.
The formula for converting a frequency $f$, in MHz, to wavelength, $\lambda$, in meters is:
$$\lambda=300/f \tag 1$$
It is clear from inspection of the formula that wavelength is inversely related to frequency. So as frequency goes down, the wavelength increases.