Sure thing! We've got 513 and we're gonna multiply it by 42. That's the same as adding 513 to itself 42 times.
Step 1: 0 + 513 = 513
Step 2: 513 + 513 = 1026
Step 3: 1026 + 513 = 1539
Step 4: 1539 + 513 = 2052
Step 5: 2052 + 513 = 2565
Step 6: 2565 + 513 = 3078
Step 7: 3078 + 513 = 3591
Step 8: 3591 + 513 = 4104
Step 9: 4104 + 513 = 4617
Step 10: 4617 + 513 = 5130
Step 11: 5130 + 513 = 5643
Step 12: 5643 + 513 = 6156
Step 13: 6156 + 513 = 6669
Step 14: 6669 + 513 = 7182
Step 15: 7182 + 513 = 7695
Step 16: 7695 + 513 = 8208
Step 17: 8208 + 513 = 8721
Step 18: 8721 + 513 = 9234
Step 19: 9234 + 513 = 9747
Step 20: 9747 + 513 = 10260
Step 21: 10260 + 513 = 10773
Step 22: 10773 + 513 = 11286
Step 23: 11286 + 513 = 11799
Step 24: 11799 + 513 = 12312
Step 25: 12312 + 513 = 12825
Step 26: 12825 + 513 = 13338
Step 27: 13338 + 513 = 13851
Step 28: 13851 + 513 = 14364
Step 29: 14364 + 513 = 14877
Step 30: 14877 + 513 = 15390
Step 31: 15390 + 513 = 15903
Step 32: 15903 + 513 = 16416
Step 33: 16416 + 513 = 16929
Step 34: 16929 + 513 = 17442
Step 35: 17442 + 513 = 17955
Step 36: 17955 + 513 = 18468
Step 37: 18468 + 513 = 18981
Step 38: 18981 + 513 = 19494
Step 39: 19494 + 513 = 20007
Step 40: 20007 + 513 = 20520
Step 41: 20520 + 513 = 21033
Step 42: 21033 + 513 = 21546

So, 513*42 = 21546