Natural numbers
Number systems · Mathematics
Study notes
Q: Is 0 a natural number? Add the first 5 natural numbers. Step 1: By convention, natural numbers start at 1: {1, 2, 3, 4, 5, ...}. So 0 is NOT a natural number (it belongs to whole numbers). Step 2: First 5 natural numbers: 1, 2, 3, 4, 5. Step 3: Sum = 1 + 2 + 3 + 4 + 5 = 15. Shortcut: sum of first n naturals = n(n+1)/2 = 5×6/2 = 15. ✓