Let's roll up our sleeves and solve this. We have 873 and we're going to multiply it by 3, essentially adding 873 to itself 3 times.
Step 1: 0 + 873 = 873
Step 2: 873 + 873 = 1746
Step 3: 1746 + 873 = 2619

So, 873*3 = 2619