To average only the cells that contain numbers and ignore cells that contain #DIV/0, you can use the AVERAGEIF function in Excel. Here are the steps to do it:

1. Select the cell where you want to display the average.
2. Type the formula "=AVERAGEIF(range,"0")" in the formula bar, where "range" is the range of cells you want to average.
3. Press Enter to calculate the average.

Note that this formula will only work if the cells containing #DIV/0 are actually blank cells with the #DIV/0 error displayed. If the cells containing #DIV/0 are not blank, you will need to use a different formula to ignore them. One option is to use the IFERROR function to replace the #DIV/0 error with a blank cell, like this:

Where "formula" is the formula that is causing the #DIV/0 error. This will replace the error with a blank cell, which can then be included in the AVERAGEIF formula without affecting the average.