Sumatron
Train your brain with this simple and fun puzzle, you just have to sum the numbers to reach the goal, you have 60 seconds and a few more seconds per hit.
You can also play in your Apple Watch. Train your brain as well as you train your body with the Apple Watch Sumatron app.
Sumatron also provides a Glance, so you can check your high score and start a new game in your Apple Watch.