Exercises. Addition and subtraction of two natural numbers up to 20

Instructions for exercises - addition and subtraction of two natural numbers up to 20

1. The task consists of 10 examples

2. Click the button to get started exercises.

3. Use the keyboard to enter an answer

   
   
   
   

   or number keys on laptop/computer

4. Enter the answer and press the button

   Attention!!! At move to the new task this example becomes inaccessible!

5. The next task will be generated. Also, to the left of the keyboard, you can see if you solved the previous task correctly, and the points scored

6. For a correctly solved task, you will receive:

   • 10 points if you spent less than 10 seconds on the solution (green indicator )
   • 9 points if you spent 10 - 15 seconds on the solution (yellow indicator )
   • 8 points if you spent 15 - 20 seconds on the solution (orange indicator )
   • 7 points if you spent more than 20 seconds on the solution (red indicator )

7. After completing 10 tasks, you will see your result.

8. You can try to improve the result by pressing the button