WxMaxima has, under the Maxima menu, a "Restart Maxima". This clears the variables and restarts input/output numbering. This is useful when you have made some mistakes, corrected them by re-inputting lines, but maybe your numbers start at  7 instead of 1 now. By doing "Restart Maxima" and then "Evaluate all Cells" you get the numbers starting at 1 and continuing consecutively. I would like to be able to do the same.