Unlucky Thirteen falls apart whenever anyone mentions his name.
Ten is seen eating a banana and holding a glass of water while leaning on a tree, Three sneaks from behind the tree then scares Ten, causing her to drop both the banana peel and glass of water she had. Three soon clarifies that she was just excited to show off her new trick; when she attempts to do it, one of her juggling balls fall off, before all her juggling balls start to fall off; she manages to catch all of them. However, just when she was about to do it, one of them falls to the ground and she trips on it, with Ten slipping over the leftover banana peel. They both collide and create a new Numberblock.
The Numberblock happens to be Thirteen, who slips on the same exact banana peel after counting all his blocks, and splitting. After attempting to state who he is again, he soon slips on the glass and splits again. Seemingly now safe from any accidents, he states who he is once more, only to be hit by a chicken from nowhere. Thirteen soon sings a song about him being unlucky.
He manages to barely dodge most of the things that attempt to split him, however, upon saying Thirteen, he falls into pieces. Eventually, it turns out, whenever he says (or hears) his name, he automatically will break up into Ten and Three. After realizing this, Thirteen decides to change his luck up and not say his name... until the near end, where a piano crashes onto him but he survives.
- Song: Unlucky Number Thirteen
- One, Twelve (Both One and Twelve are on the ladder when Thirteen is walking under the ladder), and Eleven (offscreen, but her football/soccer ball nearly hits Thirteen, and Eleven apologizes) made a cameo in this episode.
- 0, 2, 4, 5, 6, 7, 8, and 9 (or 2, 4-9) are absent in this episode (unless you count Ten's 0 Numberling as Zero).
- List of unlucky things that happened:
- Three scaring Ten, making her drop her banana peel and glass.
- Three dropping her juggling balls.
- Three stepping on one of her balls and Ten slipping on the banana peel, causing them to make Thirteen.
- Thirteen slipping on the same banana peel, causing him to split into Ten and Three.
- Thirteen stepping on Ten's glass (from now on these events cause him to split into Ten and Three, except the ladder)
- A chicken dropping on Thirteen
- Thirteen crashing into a lamppost.
- Thirteen stepping into a puddle and slipping.
- The "don't say 13" card drops onto Thirteen.
- Thirteen stepping on the same card.
- Thirteen walking under a ladder.
- List of unlucky things that ALMOST happened:
- Thirteen getting hit by Eleven's football.
- Thirteen tripping on a rock.
- Thirteen falling into a hole.
- Thirteen splitting into Ten and Three, but he says that he is thirsty.
- Same thing, but he says that it's Thursday.
- Thirteen getting poked by two birds.
- Thirteen getting hit by a falling pot.
- Thirteen tripping on a rug.
- Thirteen getting hit by a boxing glove, which instead gives him a drink and a calendar showing Thursday.
- Thirteen getting crushed by an oversized piano.
- According to the calendar, it's Thursday the 13th, which is REALLY CLOSE to Friday the 13th.
- This is the second appearance of a piano in the Learningblocks franchise. The first was Quick.
- Three is the smallest number to speak in this episode.
- A few parts of the episode were teased in a trailer along with the previous 5 episodes, hinting that Thirteen will appear too.
- The first time Thirteen properly splits (i.e not via outer factors such as chickens) is upon clarifying he was just joking.
- During the end, the camera spins around Thirteen. Paired with the background, this is probably a reference to the very first episode, minus the fact Thirteen is constantly moving.