Algebralians[1] (also spelled Algebraliens, a portmanteau of "algebra" and "alien", and Numeral species in the book in "Thanks for 2,000,000 Subscribers!") are colorful, genderless, sentient beings resembling mathematical symbols (mostly numbers) that originate from the Equation Playground. They are notable for their appearances in "X Finds Out His Value", "The Number Playground Chronicle!", and Battle for BFB. (+ the subscribers specials), The Power of Two.
The only canonical appearances of Algebralians are from Battle for Dream Island. Their appearances in the pre-BFDI comics and Subscriber specials are considered not canon, meaning they are not part of the central universe and timeline of events.
Quick Answers
What is the origin of the Algebralians in the Battle for BFB series?
How do Algebralians resemble mathematical symbols in their appearances?
What are the notable appearances of Algebralians in the XFOHV series?
What is the significance of the Equation Playground to the Algebralians?
In what context does the term 'Numeral species' refer to Algebralians?
Species[]
Integers[]

Four, the most notable integer
- Main article: Integers
Integers are based upon numeric digits. Integers made their debut in "X Finds Out His Value", with One, Three, Four, Five, Six, Seven, and Eight making their first appearances. In "The Number Playground Chronicle!", its spiritual successor, Two, Zero, and Nine are introduced. In "Thanks for 1,000,000 subscribers!", Ten is introduced. In "Thanks for 1,500,000 Subscribers!", Fifteen and Fourteen are introduced, along with the ability for integers to merge. In "Thanks for 2,000,000 subscribers!", Twelve and Sixteen are introduced, along with the ability for integers to divide.
Equation Characters[]
- Main article: List of fusions and splits of Algebralians
Variables/Alphabets[]

X, the most notable variable
- Main article: Variables
Variables are based upon mathematical variables which used the English Alphabet or even other languages and Alphabets (as shown in "BFB 31") as a symbol. Most use or are represented by letters in the Latin alphabet. X was introduced in "X Finds Out His Value" as the very first variable, with N Variable, Y Variable, and Z Variable being introduced in "The Number Playground Chronicle!".
Possible Variables[]
Irrationals[]

Pi, the most notable Irrational
- Main article: Irrationals
Irrationals were introduced in "The Number Playground Chronicle!". One member, Pi, served as a journalist and writer for the titular newspaper, writing on articles such as Five and Three not catching balls. Irrationals reappeared in the short "Pie vs Pi: The Pi Day Massacre" and had a larger role in that short. This is their most recent appearance.
The Number Playground Chronicle![]
These species of Algebralien have exclusively been seen in "The Number Playground Chronicle!" and have not been confirmed to exist within other canons containing Algebraliens.
Polygons[]

Rectangle Polygon, the most notable polygon
- Main article: Polygons
Polygons were introduced in "The Number Playground Chronicle!". They are based upon the first 11 polygons by sides minus heptagon (7 sides) and decagon (10 sides). They did not make any more appearances after their debut.
Operators[]

Divide Operator, the most notable operator
- Main article: Operators
Operators were introduced in "The Number Playground Chronicle!". They are based upon mathematical operators. Divide Operator was the only operator to have been physically seen, until Plus, Positive, and Asterisk were introduced as recommended characters. Plus, Multiply, and Divide were later seen in Subscriber Specials as inanimate objects.
Algebraic Expressions[]
Algebraic Expressions are Algebralians made with Variables (and sometimes) integers along with constants. They can also sometimes have operations (ex. additions, substraction, devision, etc.)

Square (a to the Square) is the most notable Algebraic Expression
Polyhedrons[]

Octahedron Polyhedron, the most notable polyhedron
- Main article: Polyhedrons
Polyhedrons were introduced in "The Number Playground Chronicle!". Octahedron Polyhedron is the only polyhedron to have been physically seen.
Fractions[]
- Main article: Fractions
Fractions were introduced in "The Number Playground Chronicle!". They are the only species introduced in the aforementioned comic to have never been visually depicted.
Unseen Characters[]
Characters not seen but either mentioned or referenced.
- One Half Fraction
- One Third Fraction
- Three Fourths Fractions
- One Quarter
- Phi
- Minus Operator
- Times Operator
- Octagon
- Pentagon
- Sixth Zero
- Undecagon
- Cube
- Icosahedron
- Tetrahedron
- Dodecahedron
- Variable ‘N’
Quantifiers[]

∀, the most Notable Quantifier.
Quantifiers are Algebralians used to specify the extent to which a statement containing variables is true.
Unknown species[]

Four and X Put Together, The most Notable Algebralien with an Unknown Genus.
These Algebralians have an unknown genus. Most of these characters are recommended with the exception of Eighth Note and Infinity, and Ninty Six not even being a math symbol (although it could be argued they represent 96). (Some of the Algebralians might not even have a genus as they're variations of other Algebralians).
Variations of Algebralians[]

Fourse, The most Notable Algebralien variation.
These are the variations of the Algebralians, which may or may not be real Algebralians.
Trivia[]
- The term "Algebralian"/"Algebralien" was initially coined by fans of the show. It was later adopted by Cary Huang himself, solidifying the species' nickname as official.
- Algebraliens live for a long time, as seen in Thanks for 900,000 Subscribers! where Six and Nine spend 28,000 years getting stones for the stone-to-boot-o-tron
- Algebralians are the only characters (and species for that matter) in the series who do not identify themselves with a specific gender, due to their species not having it[2].
- Algebralians might have very fragile skin. In "X Marks the Spot", Two claims that glue can damage an Algebralian's skin, even though they never state how.
- Algebralians appear with sclerae (the whites surrounding their pupils), whereas the anthropomorphic objects are shown only with pupils.
- Algebralian digits 1-8, with the exception of five are colored based off of numbers from the game Minesweeper. This is stated in the credits of "X Finds Out His Value".
- Some algebralians have been shown to be able to retract limbs. In some scenes, Two, Pi, Fourteen, Tau, and more have been seen without certain limbs that they usually have.
- According to "The Number Playground Chronicle!", Four and X are the only algebraliens to have phones, but in "Why is the BFDI Mouth Everywhere?" and when Two "Checks if they have voted," Two has a gray phone of their own, with the words "Two's awesome phone" on the back of it.
- Like objects, Algebralians can die, as proven in several BFB episodes where Four kills X by despawning him.
- Algebralians have presumably existed for hundreds of years, as in Twosday, Two stated it has been a hundred years since the Twosday tradition.
- That means the earliest the algebralians could've ever existed would be no later than back in February 2nd, 1922.
- Algebralian assets/bodies do not flip and remain the same, even in a 3D space, regardless of whether they face backward, forward, left, or right. Only the face is moved to show which direction the algebralien is facing. This does not apply to X, since when you flip their asset, they’re still the same. This is commonly an overlooked/missed detail in fanon drawings.
- It is implied that Algebraliens have blood. When Nine was beaten up, they had visible wounds colored light red and purple. Additionally, Zero with a cap was shown blushing in the "Thanks for 2,763,000 Subscribers!" special.
- Some Algebralians cannot get hurt by lava, while some are vulnerable to the lava's heat.
- Algebraliens have bones (specifically hip bones), as Zero with a cap has broken one before in a tape.
- 4 and X have appeared the most.
Calculations[]
As most algebralians are numerical characters, they are able to fuse and subtract with each other as if they were mathematical sums. So far, six instances of algebralian calculations have been shown on the channel.
- "Four Goes Too Far", where Four and Donut (acting as Zero) multiplied to create Zero, eliminating Four. The equation appeared to not have a proper multiplication symbol (×), though it is theorized that A Better Name Than That's sled acted as a multiplication bracket.
- "Thanks for 1,500,000 Subscribers!", where Six and Nine added together to create Fifteen.
- It is confirmed in this video that, whenever two algebralians combine, part of one algebralian enters the other: such as Six and Nine becoming a blue-grey gradient of 15, and Four becoming Donut's filling.
- "Thanks for 2,000,000 Subscribers!", where Two divided Fourteen into two green sevens. And where Seven and "Green Seven" were added together to create Fourteen. It also had two green sevens added back to Fourteen off-screen.
- "Pie Vs Pi: The Pi Day Massacre", where Pi was divided by Zero, leaving only Zero and eliminating Pi.
References[]
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