Using EXPAND and COLLAPSE in visual calculations

See when EXPAND and COLLAPSE are required to obtain the correct result with visual calculations in Power BI.
Article and download: sql.bi/833902?aff=yt

How to learn DAX: www.sqlbi.com/guides/dax/?aff=yt
The definitive guide to DAX: www.sqlbi.com/books/the-definitive-guide-to-dax-2n…