Classical vs. Quantum Bits

While the math for the total number of combinations is the same for both classical bits and qubits, how they hold that information is entirely different:

• Classical Bits: A 100-bit classical register can only hold one of those $2^{100}$ combinations at any single point in time (e.g., just the string 01101...).
• Quantum Qubits: Thanks to superposition and entanglement, a 100-qubit system can exist in a mathematical blend of all 2^100 states simultaneously.