1. The problem asks how we know that $4^3 = 64$. 2. The expression $4^3$ means $4$ multiplied by itself 3 times: $4 \times 4 \times 4$. 3. Calculate step-by-step: first, $4 \times 4 = 16$. 4. Then multiply $16 \times 4 = 64$. 5. So, $4^3 = 64$ because multiplying 4 three times gives 64.