Let's roll up our sleeves and solve this. We have 820 and we're going to multiply it by 3, essentially adding 820 to itself 3 times.
Step 1: 0 + 820 = 820
Step 2: 820 + 820 = 1640
Step 3: 1640 + 820 = 2460

So, 820*3 = 2460