Let's roll up our sleeves and solve this. We have 561 and we're going to multiply it by 45, essentially adding 561 to itself 45 times.
Step 1: 0 + 561 = 561
Step 2: 561 + 561 = 1122
Step 3: 1122 + 561 = 1683
Step 4: 1683 + 561 = 2244
Step 5: 2244 + 561 = 2805
Step 6: 2805 + 561 = 3366
Step 7: 3366 + 561 = 3927
Step 8: 3927 + 561 = 4488
Step 9: 4488 + 561 = 5049
Step 10: 5049 + 561 = 5610
Step 11: 5610 + 561 = 6171
Step 12: 6171 + 561 = 6732
Step 13: 6732 + 561 = 7293
Step 14: 7293 + 561 = 7854
Step 15: 7854 + 561 = 8415
Step 16: 8415 + 561 = 8976
Step 17: 8976 + 561 = 9537
Step 18: 9537 + 561 = 10098
Step 19: 10098 + 561 = 10659
Step 20: 10659 + 561 = 11220
Step 21: 11220 + 561 = 11781
Step 22: 11781 + 561 = 12342
Step 23: 12342 + 561 = 12903
Step 24: 12903 + 561 = 13464
Step 25: 13464 + 561 = 14025
Step 26: 14025 + 561 = 14586
Step 27: 14586 + 561 = 15147
Step 28: 15147 + 561 = 15708
Step 29: 15708 + 561 = 16269
Step 30: 16269 + 561 = 16830
Step 31: 16830 + 561 = 17391
Step 32: 17391 + 561 = 17952
Step 33: 17952 + 561 = 18513
Step 34: 18513 + 561 = 19074
Step 35: 19074 + 561 = 19635
Step 36: 19635 + 561 = 20196
Step 37: 20196 + 561 = 20757
Step 38: 20757 + 561 = 21318
Step 39: 21318 + 561 = 21879
Step 40: 21879 + 561 = 22440
Step 41: 22440 + 561 = 23001
Step 42: 23001 + 561 = 23562
Step 43: 23562 + 561 = 24123
Step 44: 24123 + 561 = 24684
Step 45: 24684 + 561 = 25245

So, 561*45 = 25245