OK, let's work through this together. We're starting with 799 and we're going to multiply it by 40, which means we add 799 to itself 40 times.
Step 1: 0 + 799 = 799
Step 2: 799 + 799 = 1598
Step 3: 1598 + 799 = 2397
Step 4: 2397 + 799 = 3196
Step 5: 3196 + 799 = 3995
Step 6: 3995 + 799 = 4794
Step 7: 4794 + 799 = 5593
Step 8: 5593 + 799 = 6392
Step 9: 6392 + 799 = 7191
Step 10: 7191 + 799 = 7990
Step 11: 7990 + 799 = 8789
Step 12: 8789 + 799 = 9588
Step 13: 9588 + 799 = 10387
Step 14: 10387 + 799 = 11186
Step 15: 11186 + 799 = 11985
Step 16: 11985 + 799 = 12784
Step 17: 12784 + 799 = 13583
Step 18: 13583 + 799 = 14382
Step 19: 14382 + 799 = 15181
Step 20: 15181 + 799 = 15980
Step 21: 15980 + 799 = 16779
Step 22: 16779 + 799 = 17578
Step 23: 17578 + 799 = 18377
Step 24: 18377 + 799 = 19176
Step 25: 19176 + 799 = 19975
Step 26: 19975 + 799 = 20774
Step 27: 20774 + 799 = 21573
Step 28: 21573 + 799 = 22372
Step 29: 22372 + 799 = 23171
Step 30: 23171 + 799 = 23970
Step 31: 23970 + 799 = 24769
Step 32: 24769 + 799 = 25568
Step 33: 25568 + 799 = 26367
Step 34: 26367 + 799 = 27166
Step 35: 27166 + 799 = 27965
Step 36: 27965 + 799 = 28764
Step 37: 28764 + 799 = 29563
Step 38: 29563 + 799 = 30362
Step 39: 30362 + 799 = 31161
Step 40: 31161 + 799 = 31960

So, 799*40 = 31960