Alright, let's solve this math problem step by step. First, we have the number 757. 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 757 and add it to itself 20 times.
Step 1: 0 + 757 = 757
Step 2: 757 + 757 = 1514
Step 3: 1514 + 757 = 2271
Step 4: 2271 + 757 = 3028
Step 5: 3028 + 757 = 3785
Step 6: 3785 + 757 = 4542
Step 7: 4542 + 757 = 5299
Step 8: 5299 + 757 = 6056
Step 9: 6056 + 757 = 6813
Step 10: 6813 + 757 = 7570
Step 11: 7570 + 757 = 8327
Step 12: 8327 + 757 = 9084
Step 13: 9084 + 757 = 9841
Step 14: 9841 + 757 = 10598
Step 15: 10598 + 757 = 11355
Step 16: 11355 + 757 = 12112
Step 17: 12112 + 757 = 12869
Step 18: 12869 + 757 = 13626
Step 19: 13626 + 757 = 14383
Step 20: 14383 + 757 = 15140

So, 757*20 = 15140