Input the real number
After selecting the square to enter, click the red number on the right.
Click "X" to delete the entered number.

Input the temporary number
You can enter up to 4 possible numbers as temporary numbers.
After selecting the square to enter, click the white number on the right.
"#" is blank, and to delete it, click the "X" above.
If you want to change the temporary number to the real number, you can enter it as it is.
If you want to change the real number to the temporary number,please erase it with "X".
It is also possible to enter collectively outside the frame instead of for each square.

Check function
In any of the following cases, an "NG" mark will appear and the input will be cancelled.　
(1)When 1 or 9 is entered in a square with a double arrows.
(2)If you enter the same number as the number that appears.
(3)If you enter a number that contradicts the arrow of the number that appears.
*It simply prevents input errors and does not judge whether the number is correct or incorrect.
*The check function does not work on temporary numbers.
　
Explanation of buttons
[Confirm] If there is an error, the number will be displayed and the limit will be reduced by one.If correct, the count does not decrease.
[Check] Turns the check function on/off. Default is on.
If you turn it on from the middle, the numbers you have already entered will not be checked.
[Single] Displays squares that do not have double arrows among the unentered squares.
[Save] You can save one for each of 1 and 2.
[Load] Open the saved number problem and read it.
[Delete] Delete the saved data. Deleted data cannot be restored.
[Next][Previous] You can change the question at any time, but the entered numbers will be erased.
[Erase] Erases all entered numbers and returns to the initial state.
[Exit] Return to the top page.

*Be careful of the volume as a sound effect will be played when the answer is correct.