docs: add some jsdoc to formatNum

src/utils/formatNum.ts

@@ -1,7 +1,14 @@
 const intlCurrencyFmt = new Intl.NumberFormat("en-US", { style: "currency", currency: "USD" });
 const intlPercentageFmt = new Intl.NumberFormat("en-US", { style: "percent" });
 
+/**
+ * These methods take as an argument a *WHOLE* integer (do not include any decimal places)
+ * and returns a string representation based on expected units using the `en-US` locale.
+ *
+ * - toCurrencyStr `123456` becomes `"$1,234.56"`
+ * - toPercentageStr `123` becomes `"123%"`
+ */
 export const formatNum = {
-  toCurrencyStr: (num: number) => intlCurrencyFmt.format(num),
+  toCurrencyStr: (num: number) => intlCurrencyFmt.format(num / 100),
   toPercentageStr: (num: number) => intlPercentageFmt.format(num)
 };