Sure! Here's an example of an educational game in which the player helps the Number King protect Numberland by solving mathematical problems. The game is implemented in a single HTML file with JavaScript embedded within script tags. Please note that this is a simple example and can be expanded upon for more complexity.
Number King - Math Defender
In this game, the Number King is represented by the unicode character `\u265A` (a pictogram of a crown). The game generates a random math problem consisting of two operands and an operator (+, -, or ×) for the player to solve. The player needs to press the corresponding number key on their smartphone keypad to submit their answer. If the answer is correct, a new problem is generated, and if it is wrong, they are prompted to try again.
This simple game can be further enhanced with additional game elements, scoring, levels, and more complex math problems to suit the educational needs and grade level.