OK, let's work through this together. We're starting with 498 and we're going to multiply it by 31, which means we add 498 to itself 31 times.
Step 1: 0 + 498 = 498
Step 2: 498 + 498 = 996
Step 3: 996 + 498 = 1494
Step 4: 1494 + 498 = 1992
Step 5: 1992 + 498 = 2490
Step 6: 2490 + 498 = 2988
Step 7: 2988 + 498 = 3486
Step 8: 3486 + 498 = 3984
Step 9: 3984 + 498 = 4482
Step 10: 4482 + 498 = 4980
Step 11: 4980 + 498 = 5478
Step 12: 5478 + 498 = 5976
Step 13: 5976 + 498 = 6474
Step 14: 6474 + 498 = 6972
Step 15: 6972 + 498 = 7470
Step 16: 7470 + 498 = 7968
Step 17: 7968 + 498 = 8466
Step 18: 8466 + 498 = 8964
Step 19: 8964 + 498 = 9462
Step 20: 9462 + 498 = 9960
Step 21: 9960 + 498 = 10458
Step 22: 10458 + 498 = 10956
Step 23: 10956 + 498 = 11454
Step 24: 11454 + 498 = 11952
Step 25: 11952 + 498 = 12450
Step 26: 12450 + 498 = 12948
Step 27: 12948 + 498 = 13446
Step 28: 13446 + 498 = 13944
Step 29: 13944 + 498 = 14442
Step 30: 14442 + 498 = 14940
Step 31: 14940 + 498 = 15438

So, 498*31 = 15438