Let's roll up our sleeves and solve this. We have 839 and we're going to multiply it by 3, essentially adding 839 to itself 3 times.
Step 1: 0 + 839 = 839
Step 2: 839 + 839 = 1678
Step 3: 1678 + 839 = 2517

So, 839*3 = 2517