Another subset of PTs relied on the “rounding rule”
(Stacey, 2005; Steinle & Stacey, 2004), viewing decimals such as 0.799 and 0.80 as the
same—“0.80 is the result of rounding 0.799” (p. 125)—so there are no decimals in between
them. Some PTs subtracted the two given decimals to find the number of decimals in
between. Widjaja et al. (2008) attribute PTs’ challenges with the density of decimals to the
lack of opportunity to work with decimals that are not the same length. In addition, PTs
must understand that the discreteness of whole numbers does not apply to decimals.