OK, let's crack this. We're given 901 and our task is to multiply it by 44. Essentially, we'll be adding 901 to itself 44 times.
Step 1: 0 + 901 = 901
Step 2: 901 + 901 = 1802
Step 3: 1802 + 901 = 2703
Step 4: 2703 + 901 = 3604
Step 5: 3604 + 901 = 4505
Step 6: 4505 + 901 = 5406
Step 7: 5406 + 901 = 6307
Step 8: 6307 + 901 = 7208
Step 9: 7208 + 901 = 8109
Step 10: 8109 + 901 = 9010
Step 11: 9010 + 901 = 9911
Step 12: 9911 + 901 = 10812
Step 13: 10812 + 901 = 11713
Step 14: 11713 + 901 = 12614
Step 15: 12614 + 901 = 13515
Step 16: 13515 + 901 = 14416
Step 17: 14416 + 901 = 15317
Step 18: 15317 + 901 = 16218
Step 19: 16218 + 901 = 17119
Step 20: 17119 + 901 = 18020
Step 21: 18020 + 901 = 18921
Step 22: 18921 + 901 = 19822
Step 23: 19822 + 901 = 20723
Step 24: 20723 + 901 = 21624
Step 25: 21624 + 901 = 22525
Step 26: 22525 + 901 = 23426
Step 27: 23426 + 901 = 24327
Step 28: 24327 + 901 = 25228
Step 29: 25228 + 901 = 26129
Step 30: 26129 + 901 = 27030
Step 31: 27030 + 901 = 27931
Step 32: 27931 + 901 = 28832
Step 33: 28832 + 901 = 29733
Step 34: 29733 + 901 = 30634
Step 35: 30634 + 901 = 31535
Step 36: 31535 + 901 = 32436
Step 37: 32436 + 901 = 33337
Step 38: 33337 + 901 = 34238
Step 39: 34238 + 901 = 35139
Step 40: 35139 + 901 = 36040
Step 41: 36040 + 901 = 36941
Step 42: 36941 + 901 = 37842
Step 43: 37842 + 901 = 38743
Step 44: 38743 + 901 = 39644

So, 901*44 = 39644