Sure thing! We've got 866 and we're gonna multiply it by 39. That's the same as adding 866 to itself 39 times.
Step 1: 0 + 866 = 866
Step 2: 866 + 866 = 1732
Step 3: 1732 + 866 = 2598
Step 4: 2598 + 866 = 3464
Step 5: 3464 + 866 = 4330
Step 6: 4330 + 866 = 5196
Step 7: 5196 + 866 = 6062
Step 8: 6062 + 866 = 6928
Step 9: 6928 + 866 = 7794
Step 10: 7794 + 866 = 8660
Step 11: 8660 + 866 = 9526
Step 12: 9526 + 866 = 10392
Step 13: 10392 + 866 = 11258
Step 14: 11258 + 866 = 12124
Step 15: 12124 + 866 = 12990
Step 16: 12990 + 866 = 13856
Step 17: 13856 + 866 = 14722
Step 18: 14722 + 866 = 15588
Step 19: 15588 + 866 = 16454
Step 20: 16454 + 866 = 17320
Step 21: 17320 + 866 = 18186
Step 22: 18186 + 866 = 19052
Step 23: 19052 + 866 = 19918
Step 24: 19918 + 866 = 20784
Step 25: 20784 + 866 = 21650
Step 26: 21650 + 866 = 22516
Step 27: 22516 + 866 = 23382
Step 28: 23382 + 866 = 24248
Step 29: 24248 + 866 = 25114
Step 30: 25114 + 866 = 25980
Step 31: 25980 + 866 = 26846
Step 32: 26846 + 866 = 27712
Step 33: 27712 + 866 = 28578
Step 34: 28578 + 866 = 29444
Step 35: 29444 + 866 = 30310
Step 36: 30310 + 866 = 31176
Step 37: 31176 + 866 = 32042
Step 38: 32042 + 866 = 32908
Step 39: 32908 + 866 = 33774

So, 866*39 = 33774