| --- |
| source: ncert |
| topic: numbers |
| class_level: class_6 |
| chapter: ch2 |
| difficulty: beginner |
| --- |
| |
| Class 6 | Ch2: Whole Numbers |
| Natural Numbers: 1,2,3,... Whole Numbers: 0,1,2,3,... (0 is whole but NOT natural) |
| Properties: Closure(a+b and a×b always whole), Commutativity(a+b=b+a), Associativity, Distributivity(a×(b+c)=a×b+a×c) |
| Identity: a+0=a (additive), a×1=a (multiplicative). Zero property: a×0=0. |
| Predecessor of n=n-1. Successor of n=n+1. |
| Triangular numbers: 1,3,6,10,15 (n(n+1)/2). Square numbers: 1,4,9,16,25. |
| Sum 1+2+...+100 = 100×101/2 = 5050. |
| Common mistake: 0 is NOT natural. Subtraction/division NOT always closed for whole numbers. |
