Math.random() generates a random number between 0 and 0.999...
0.8706439702609821
Math.random() * 10 generates a random number between 0 and 9.999...
8.70643970260982
Math.floor(Math.random() * 10) generates a random whole number between 0 and 9
8
To generate a random number in a different range, multiply Math.random() by a different number.