Insert a formula in a table cell. Scroll down and click PRODUCT as shown. In older versions of Word this appears as the Layout tab of the Table Tools contextual tab in the Ribbon.
Click the table cell where you want your result to appear.
Depending on the size of your screen you may have to click the Data button first. Position the cursor where you want to paste a formula. A dialog named Formula is displayed typing in the formula text. Select the formula cell and hover the mouse cursor over a small square at the lower right-hand corner until it changes to a thick black cross.