How to add An HTML table with a table cell that spans two columns

<!DOCTYPE html> <html> <head> <style> table, th, td { border: 1px solid black; } </style> </head> <body> <h1>The td colspan attribute</h1> <table> <tr> <th>Month</th> <th>Savings</th> </tr> <tr> <td>January</td> <td>$100</td> </tr> <tr> <td>February</td> <td>$80</td> </tr> <tr> <td colspan="2">Sum: $180</td> </tr> </table> </body> </html>