OK, let's crack this. We're given 841 and our task is to multiply it by 4. Essentially, we'll be adding 841 to itself 4 times.
Step 1: 0 + 841 = 841
Step 2: 841 + 841 = 1682
Step 3: 1682 + 841 = 2523
Step 4: 2523 + 841 = 3364

So, 841*4 = 3364