Confused with multiple controls and dynamically created controls

Hi I have two buttons, three textboxes and two labels. I want the users to fill out the textboxes to know how many columns and rows of the textboxes need to be created. Then I want to user to click on button 1 to create the textboxes. Then the users fill out the columns by rows number of textboxes with integers. Then click on button 2 to find the sum on textbox3. When the user clicks on button 2, there is post back and it deletes all my dynamically created textboxes and does not show anything on textbox3. Should I just use html button for button2 or do I somehow prevent postback but make sure the code behind still run? 
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