The game description was provided. My approach is documented in the following paragraphs.
My understanding from the document was that the game would be ideal as an interactive medium for teaching kids addition/subtraction. So, I took kid-friendliness as a deciding factor. The graphics and gameplay adjustments were chosen with this in mind.
I made out a rough sketch following the description provided.
I took some liberties in tweaking some of the instructions to make it more suitable to kids.
The initial plan was to have two Easy/Regular difficulty modes, which I later replace with a Timed mode, which runs for 90 seconds. The game is still flexible to having multiple difficulty modes with modifiable difficulty multipliers, if we feel the need to switch to that approach later.
I also made sure to have more valid pairs generated because otherwise the game does not seem fair. There is still an 8% chance to have an invalid pair to be generated.
I prepared two different art-styles, Minimalistic & Flat Themed, and Traditional Stylized Art.
I opted for the second one as I felt it would be more attractive toward the young consumers. The shapes of the buttons and UI elements were also decided on this factor. I tried to stick to the following simple color palette.
