Alright, let's solve this math problem step by step. First, we have the number 397. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 20. So, we're going to take the number 397 and add it to itself 20 times.
Step 1: 0 + 397 = 397
Step 2: 397 + 397 = 794
Step 3: 794 + 397 = 1191
Step 4: 1191 + 397 = 1588
Step 5: 1588 + 397 = 1985
Step 6: 1985 + 397 = 2382
Step 7: 2382 + 397 = 2779
Step 8: 2779 + 397 = 3176
Step 9: 3176 + 397 = 3573
Step 10: 3573 + 397 = 3970
Step 11: 3970 + 397 = 4367
Step 12: 4367 + 397 = 4764
Step 13: 4764 + 397 = 5161
Step 14: 5161 + 397 = 5558
Step 15: 5558 + 397 = 5955
Step 16: 5955 + 397 = 6352
Step 17: 6352 + 397 = 6749
Step 18: 6749 + 397 = 7146
Step 19: 7146 + 397 = 7543
Step 20: 7543 + 397 = 7940

So, 397*20 = 7940