Alright, let's solve this math problem step by step. First, we have the number 870. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 3. So, we're going to take the number 870 and add it to itself 3 times.
Step 1: 0 + 870 = 870
Step 2: 870 + 870 = 1740
Step 3: 1740 + 870 = 2610

So, 870*3 = 2610