Decimal (Base 10)
Standard counting system using digits 0-9. Each position represents a power of 10.
123₁₀ = 1×10² + 2×10¹ + 3×10⁰ = 100 + 20 + 3 = 123₁₀
Binary (Base 2)
Uses only digits 0 and 1. Each position represents a power of 2.
1011₂ = 1×2³ + 0×2² + 1×2¹ + 1×2⁰ = 8 + 0 + 2 + 1 = 11₁₀
Converting from Decimal
Use repeated division by target base, collecting remainders from bottom to top.
25₁₀ to binary: 25÷2=12 r1, 12÷2=6 r0, 6÷2=3 r0, 3÷2=1 r1, 1÷2=0 r1 → 11001₂