'README.md' updaten

README.md

@@ -48,10 +48,10 @@ Use the LIMIT clause so the result set contains only the rows with the 5 largest
 
 Write a SELECT statement that returns these columns from the Invoices table:
 
-invoice_number (The invoice_number column)
-invoice_date (The invoice_date column)
-balance_due (The invoice_total column minus the payment_total and credit_total columns)
-payment_date (The payment_date column)
+**invoice_number** (The invoice_number column)  
+**invoice_date** (The invoice_date column)  
+**balance_due** (The invoice_total column minus the payment_total and credit_total columns)  
+**payment_date** (The payment_date column)  
 
 Return only the rows where the payment_date column contains a null value. This should retrieve 11 rows.