Step 1th, open the Word2010 document window, click the formula you want to add an operator to, and position the insertion cursor in the target location, as shown in Figure 1.
Figure 1 Click the formula you want to add an operator to
Step 2nd, click the other button in the symbol group in the formula Tools/design ribbon to open the symbol panel, and then click the Drop-down triangle button at the top. Select the operator option from the Open Drop-down menu and select the operator you want in the Open operator panel, as shown in Figure 2.
Figure 2 Selecting the Add operator