In Excel 20 10 workbook, the maximum number of worksheets can only be limited by available memory. However, by default, only three open worksheets are displayed in the workbook opened by Excel.

We can insert a new worksheet into the workbook in the following ways.

Click the Insert Sheet button on the Sheet tab to insert the sheet at the end of the existing sheet.

Click the worksheet tab with the right mouse button, select the Insert command from the pop-up shortcut menu, open the Insert dialog box, select the worksheet icon, click OK, and insert a worksheet before clicking the worksheet tab with the right mouse button.

Click the small arrow to the right of the Insert button in the Start ribbon, and then click the Insert Sheet command in the expanded drop-down menu (or press the shift key plus F 1, shift key plus gear key plus F 1) to insert a worksheet before the current worksheet.

I hope it can help you solve the problem.