Let's roll up our sleeves and solve this. We have 38 and we're going to multiply it by 21, essentially adding 38 to itself 21 times.
Step 1: 0 + 38 = 38
Step 2: 38 + 38 = 76
Step 3: 76 + 38 = 114
Step 4: 114 + 38 = 152
Step 5: 152 + 38 = 190
Step 6: 190 + 38 = 228
Step 7: 228 + 38 = 266
Step 8: 266 + 38 = 304
Step 9: 304 + 38 = 342
Step 10: 342 + 38 = 380
Step 11: 380 + 38 = 418
Step 12: 418 + 38 = 456
Step 13: 456 + 38 = 494
Step 14: 494 + 38 = 532
Step 15: 532 + 38 = 570
Step 16: 570 + 38 = 608
Step 17: 608 + 38 = 646
Step 18: 646 + 38 = 684
Step 19: 684 + 38 = 722
Step 20: 722 + 38 = 760
Step 21: 760 + 38 = 798

So, 38*21 = 798