OK, let's work through this together. We're starting with 803 and we're going to multiply it by 43, which means we add 803 to itself 43 times.
Step 1: 0 + 803 = 803
Step 2: 803 + 803 = 1606
Step 3: 1606 + 803 = 2409
Step 4: 2409 + 803 = 3212
Step 5: 3212 + 803 = 4015
Step 6: 4015 + 803 = 4818
Step 7: 4818 + 803 = 5621
Step 8: 5621 + 803 = 6424
Step 9: 6424 + 803 = 7227
Step 10: 7227 + 803 = 8030
Step 11: 8030 + 803 = 8833
Step 12: 8833 + 803 = 9636
Step 13: 9636 + 803 = 10439
Step 14: 10439 + 803 = 11242
Step 15: 11242 + 803 = 12045
Step 16: 12045 + 803 = 12848
Step 17: 12848 + 803 = 13651
Step 18: 13651 + 803 = 14454
Step 19: 14454 + 803 = 15257
Step 20: 15257 + 803 = 16060
Step 21: 16060 + 803 = 16863
Step 22: 16863 + 803 = 17666
Step 23: 17666 + 803 = 18469
Step 24: 18469 + 803 = 19272
Step 25: 19272 + 803 = 20075
Step 26: 20075 + 803 = 20878
Step 27: 20878 + 803 = 21681
Step 28: 21681 + 803 = 22484
Step 29: 22484 + 803 = 23287
Step 30: 23287 + 803 = 24090
Step 31: 24090 + 803 = 24893
Step 32: 24893 + 803 = 25696
Step 33: 25696 + 803 = 26499
Step 34: 26499 + 803 = 27302
Step 35: 27302 + 803 = 28105
Step 36: 28105 + 803 = 28908
Step 37: 28908 + 803 = 29711
Step 38: 29711 + 803 = 30514
Step 39: 30514 + 803 = 31317
Step 40: 31317 + 803 = 32120
Step 41: 32120 + 803 = 32923
Step 42: 32923 + 803 = 33726
Step 43: 33726 + 803 = 34529

So, 803*43 = 34529