1) Braces cannot be directly entered by keyboard, and need to be inserted with "Ctrl" key +F9; Or choose "insert" on the menu >; "Domain", select "If" in the "Domain Name" drop-down box, and a domain code box will appear on the right. Just enter the corresponding content.

2) When using the if function in word, the directly quoted cell name is invalid (other mathematical formulas are valid), so you need to specify the book signature for the referenced cell (or data). Method: After selecting a cell (or data), select "Insert" on menu >; Bookmark, give it a name.

3) There must be spaces before and after "="