This is Math Book's ref sheet, you can check out their full bio in my Toyhouse here!
Math Book's Toyhouse

Name: Math Book
Age: ??? (Adult age)
Gender: Non-Binary
Pronouns: They/them
Species: Object (Math Notebook)
Sexuality: Pansexual
Job/Occupation: Unknown

Personality: An extremely introverted Math Notebook that’s obsessed with writing down research of non-object kind, especially the Algebraliens. You would mainly see them sitting down, vigorously writing down in their notepad of all the unnatural things that occur on Earth or even doing a little QnA session with one of the Algebraliens: Four, X and Two. They are seen with Four the most as they both bonded from the very start of Battle For BFDI, getting along with their experiences of being weird in different but similar ways.

Important notes:

• They always carry their research notebook, they just keep it safe within their pages.
• They use the nickname ‘MB’.
• If you open them, their pages are filled with math equations and math problems.

Design Notes:

• They are 6 inches shorter than Four for size comparison.
• Mouth and limbs can be drawn in the show’s original style.
• They always have their glasses on.