Sure thing! We've got 42 and we're gonna multiply it by 19. That's the same as adding 42 to itself 19 times.
Step 1: 0 + 42 = 42
Step 2: 42 + 42 = 84
Step 3: 84 + 42 = 126
Step 4: 126 + 42 = 168
Step 5: 168 + 42 = 210
Step 6: 210 + 42 = 252
Step 7: 252 + 42 = 294
Step 8: 294 + 42 = 336
Step 9: 336 + 42 = 378
Step 10: 378 + 42 = 420
Step 11: 420 + 42 = 462
Step 12: 462 + 42 = 504
Step 13: 504 + 42 = 546
Step 14: 546 + 42 = 588
Step 15: 588 + 42 = 630
Step 16: 630 + 42 = 672
Step 17: 672 + 42 = 714
Step 18: 714 + 42 = 756
Step 19: 756 + 42 = 798

So, 42*19 = 798