سوال ۲۳ کنکور ارشد ریاضی ۱۴۰۲

PASSAGE 3 (paragraph 1):

All methods allow a change of the steplength in each integration step; an adjustment of the respective stepsizes in each of them does not run into any inherent difficulties. The modern multistep methods are not employed with fixed orders; nor are the extrapolation methods. In extrapolation methods, for example, one can easily increase the order by appending another column to the tableau of extrapolated values. One-step methods of the Runge-Kutta-Fehlberg type, by construction, are tied to a fixed order, although methods of variable orders can also be constructed with correspondingly more complicated procedures. Research on this is currently in progress.

23- What does the underlined word "appending" in paragraph 1 mean?