Excel Tip – The Format of an Inserted Column
Un-beknown to most, when you insert a new column, the Format of the cells in the Column are of the cells in the Column on the Left. So, if you get a Date when you enter a number as with the example shown, you would have inserted the column to the right of a Date Formatted Field.
This can be useful if that was your intention, but most of the time it isn’t. To override this default, use the Insert Options (little Paintbrush) to change the Format; either to the Column on the right or Clear the Formatting altogether.