Don't let the simple layout fool you, this is teacher gold!
This 22 slide PowerPoint presentation is for using mental math to estimate differences. Problems include subtracting multiples of 10 and estimating by rounding to the nearest 10.
The math problems can be changed over and over for as many different games as you can imagine. I've created a template that you can use over and over with your own problems. Problems are shown and answers fly in on click.
My students love it!