1. The problem is to understand why the multiplication $2 \times 1 \times 1 = 2$.\n\n2. The formula used here is the multiplication of numbers, which means combining quantities. The rule is that multiplying any number by 1 leaves the number unchanged.\n\n3. Let's break it down step-by-step:\n- First, multiply $2 \times 1 = 2$. Multiplying by 1 does not change the value.\n- Next, multiply the result by 1 again: $2 \times 1 = 2$.\n\n4. So, the entire expression $2 \times 1 \times 1$ simplifies to $2$.\n\n5. In plain language, multiplying by 1 means you keep the original number the same, so multiplying by 1 multiple times still results in the original number.