the "silhouettes" of the numbers (0−9) are used. For example, the number 6 is any hollow closed (void) figure (even if it is a triangle or any other figure) with a stick on top;
rotation or mirroring of numbers does not change their meaning, with the exception of numbers 2 and 5 (they change to each other when mirrored), as well as 6 and 9 (they change to each other when rotated);
read from left to right;
read from top to bottom, if the above does not apply;
attention to details, open lines;
common sense!
one work — one number;
Arabic numerals;
the "silhouettes" of the numbers (0−9) are used. For example, the number 6 is any hollow closed figure (even if it is a triangle or any other figure) with a stick on top;
rotation or mirror image of numbers does not change their meaning, with the exception of numbers 2 and 5, as well as 6 and 9;
read from left to right;
read from top to bottom, if item 5 above does not apply;