OK, let's work through this together. We're starting with 384 and we're going to multiply it by 40, which means we add 384 to itself 40 times.
Step 1: 0 + 384 = 384
Step 2: 384 + 384 = 768
Step 3: 768 + 384 = 1152
Step 4: 1152 + 384 = 1536
Step 5: 1536 + 384 = 1920
Step 6: 1920 + 384 = 2304
Step 7: 2304 + 384 = 2688
Step 8: 2688 + 384 = 3072
Step 9: 3072 + 384 = 3456
Step 10: 3456 + 384 = 3840
Step 11: 3840 + 384 = 4224
Step 12: 4224 + 384 = 4608
Step 13: 4608 + 384 = 4992
Step 14: 4992 + 384 = 5376
Step 15: 5376 + 384 = 5760
Step 16: 5760 + 384 = 6144
Step 17: 6144 + 384 = 6528
Step 18: 6528 + 384 = 6912
Step 19: 6912 + 384 = 7296
Step 20: 7296 + 384 = 7680
Step 21: 7680 + 384 = 8064
Step 22: 8064 + 384 = 8448
Step 23: 8448 + 384 = 8832
Step 24: 8832 + 384 = 9216
Step 25: 9216 + 384 = 9600
Step 26: 9600 + 384 = 9984
Step 27: 9984 + 384 = 10368
Step 28: 10368 + 384 = 10752
Step 29: 10752 + 384 = 11136
Step 30: 11136 + 384 = 11520
Step 31: 11520 + 384 = 11904
Step 32: 11904 + 384 = 12288
Step 33: 12288 + 384 = 12672
Step 34: 12672 + 384 = 13056
Step 35: 13056 + 384 = 13440
Step 36: 13440 + 384 = 13824
Step 37: 13824 + 384 = 14208
Step 38: 14208 + 384 = 14592
Step 39: 14592 + 384 = 14976
Step 40: 14976 + 384 = 15360

So, 384*40 = 15360