Alright, let's solve this math problem step by step. First, we have the number 789. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 5. So, we're going to take the number 789 and add it to itself 5 times.
Step 1: 0 + 789 = 789
Step 2: 789 + 789 = 1578
Step 3: 1578 + 789 = 2367
Step 4: 2367 + 789 = 3156
Step 5: 3156 + 789 = 3945

So, 789*5 = 3945