diff --git a/main.ts b/main.ts
index 3640d8d..93e0669 100644
--- a/main.ts
+++ b/main.ts
@@ -249,15 +249,15 @@ class MathTypeSuggest extends EditorSuggest<string> {
 		const editor = this.context.editor;
 		const lineContent = editor.getLine(this.context.start.line);
 
-		if (!lineContent.startsWith("$") && !lineContent.endsWith("$")) {
+		if (lineContent.startsWith("$") && lineContent.endsWith("$")) {
 			editor.replaceRange(
-				`$${value}$`,
+				value,
 				this.context.start,
 				this.context.end
 			);
 		} else {
 			editor.replaceRange(
-				value,
+				`$${value}$`,
 				this.context.start,
 				this.context.end
 			);