I need a condition to do a certain job everytime a thousand value is passed

So let's say i have a variable called score. My game is running and my score is going up . What i want to the if statement is every time my game reaches +1000 score to do a certain job in my case to change a color of a ball , but thats not the case of the question. For example - my score starts on 0 and the color of the ball is green , when it reaches 1000 the color of the ball changes , when it reaches 2000 it changes again , on 3000 again etc. i only need the if statement , not the color changer.