Insert cells (not rows)

In Excel, the simple task of adding (and deleting) cells, without compromising the row (i.e. adding or deleting the row) is frustratingly missing in Numbers. I often add cells; which only shifts the cells either up or down. The rest of the row is not disturbed. I would like to start regularly using Numbers, but without this simple function that will be impossible. If there is a way to do this in Numbers, please advise. Thanks.