Using the numbers [6, 77, 20, 3], construct an equation that equals 100. You are allowed to use basic arithmetic operations (+, -, *, /) and each number can only be used once. Show your steps in the <think> section, and state the final equation and answer in the <answer> section, as shown below:
<answer>
3 * (20 + 77) - 6 = 100
</answer>
</think>