The very first thing I did even before compiling the code was to uncomment import java.awt.Font coz that stood out immediately xD. Then the syntax errors of not terminating the instructions with a semicolon (;), not following case sensitivity and the logical errors like swapped radio buttons for Start and Stop, or the wrong count starting from 23 with an increment of 23 per wrong answer. Also, there was an issue with showing the count of correct answers, it was moving along the wrong side of the number line. There were other issues too like add and multiply radio buttons were swapped. These are the errors I am able to recall.