Connect Four App for percentages or rounding

Simple but effective resource - please rate! Three versions of connect-4 to encourage students to interact: 1) with percentages on the virtual board, where students convert them to decimals (or fractions); 2) with a random number generator and different rounding methods, where students try to round to the correct degree of accuracy; 3) create your own by adding a file named input.txt in the same folder with the desired text for the virtual connect four board. The coloured counter is placed if you pick a colour and click on the desired part of the board.