Prime and Composite: The Star Tower
Welcome to the Star Tower! Professor Luna Moon lays out her paper stars in rectangles. Some numbers of stars make lots of rectangles, but some can only make one long row: those are the prime numbers.
Remember: A prime number has exactly 2 factors: 1 and itself (2, 3, 5, 7, 11, 13…). A composite number has more than 2 factors (4, 6, 8, 9…). 1 is neither: it has only 1 factor.
Magic trick: 2 is the only even prime. Every other even number can be split into 2 equal rows, so it is composite.
Seek and Find
Look carefully at the picture of the Star Tower and find:
- ⭐ Find the gold stars on the table. 7 stars can only make one long row: 7 is a prime number.
- ✨ Find the silver stars on the board. 2 rows of 3 = 6 stars. 6 makes a rectangle, so it is composite.
- 🪐 Find the planet globes. Count them: 3 globes. 3 is prime too!
- 🐱 Millie and her kitten Biscuit are hiding in every picture. Can you spot them?