OK, let's work through this together. We're starting with 57 and we're going to multiply it by 12, which means we add 57 to itself 12 times.
Step 1: 0 + 57 = 57
Step 2: 57 + 57 = 114
Step 3: 114 + 57 = 171
Step 4: 171 + 57 = 228
Step 5: 228 + 57 = 285
Step 6: 285 + 57 = 342
Step 7: 342 + 57 = 399
Step 8: 399 + 57 = 456
Step 9: 456 + 57 = 513
Step 10: 513 + 57 = 570
Step 11: 570 + 57 = 627
Step 12: 627 + 57 = 684

So, 57*12 = 684