1. **State the problem:** Calculate the product of 16 and 4. 2. **Formula used:** Multiplication of two numbers $a$ and $b$ is given by $a \times b$. 3. **Apply the formula:** Here, $a=16$ and $b=4$, so we calculate $16 \times 4$. 4. **Intermediate work:** Multiply 16 by 4: $$16 \times 4 = 64$$ 5. **Final answer:** The product of 16 and 4 is $64$.