Mathematics = the search for patterns + the search for explanations of why those patterns exist.
Patterns exist everywhere — in nature, shopping, cooking, games, weather & technology! Maths is both an art and a science.
Number theory = branch of maths that studies patterns in whole numbers (0,1,2,3,...). The most basic pattern-type: number sequences.
| Sequence | Numbers | Rule 🔑 |
|---|---|---|
| All 1's | 1,1,1,1,... | same number repeats |
| Counting | 1,2,3,4,... | +1 each time |
| Odd | 1,3,5,7,... | +2 each time (start 1) |
| Even | 2,4,6,8,... | +2 each time (start 2) |
| Triangular | 1,3,6,10,15,... | add next counting no. |
| Squares | 1,4,9,16,25,... | n × n |
| Cubes | 1,8,27,64,125,... | n × n × n |
| Virahānka | 1,2,3,5,8,13,... | sum of previous 2 |
| Powers of 2 | 1,2,4,8,16,... | × 2 each time |
| Powers of 3 | 1,3,9,27,81,... | × 3 each time |
Pictures make sequences easier to understand! e.g. Triangular numbers form triangles of dots, Squares form square grids, Cubes form 3-D cube stacks.
36 is BOTH a triangular number and a square number — 36 dots arrange perfectly as a triangle and as a 6×6 square!
⬡Hexagonal numbers: 1, 7, 19, 37, ... (dots arranged in hexagon shape)
Sequences can connect to each other in beautiful ways!
gives 1, 4, 9, 16 ... → the Square Numbers! 🟦
Geometry = branch of maths that studies patterns in shapes (1D, 2D, 3D or more!). Shape sequences studied:
| Shape Sequence | Connected Number Sequence |
|---|---|
| Regular Polygons (sides = corners) | 3,4,5,6,7,8,9,10 (Counting nos. from 3) |
| Complete Graphs (no. of lines) | 1,3,6,10,15 (Triangular numbers) |
| Stacked Squares (little squares) | 1,4,9,16,25 (Square numbers) |
| Stacked Triangles (little triangles) | 1,4,9,16,25 (Square numbers) |
| Koch Snowflake (line segments) | 3,12,48,192 (3 × Powers of 4) |
Triangular numbers × 6 + 1 → gives Hexagonal numbers (7, 19, 37, 61, 91...)