Using an app can help you exercise your ability to perform fast calculations.
We have both simple and difficult modes. The simple mode is a 1-10 addition, subtraction, multiplication, and division operation, while the difficult mode is a 10-100 operation. The app requires you to choose the correct answer within 10, give 5 points for the right one, deduct 5 points for the wrong one, and continue until 0 points.
Each time it ends, a score record will be generated for you to review later.