Sure thing! We've got 204 and we're gonna multiply it by 20. That's the same as adding 204 to itself 20 times.
Step 1: 0 + 204 = 204
Step 2: 204 + 204 = 408
Step 3: 408 + 204 = 612
Step 4: 612 + 204 = 816
Step 5: 816 + 204 = 1020
Step 6: 1020 + 204 = 1224
Step 7: 1224 + 204 = 1428
Step 8: 1428 + 204 = 1632
Step 9: 1632 + 204 = 1836
Step 10: 1836 + 204 = 2040
Step 11: 2040 + 204 = 2244
Step 12: 2244 + 204 = 2448
Step 13: 2448 + 204 = 2652
Step 14: 2652 + 204 = 2856
Step 15: 2856 + 204 = 3060
Step 16: 3060 + 204 = 3264
Step 17: 3264 + 204 = 3468
Step 18: 3468 + 204 = 3672
Step 19: 3672 + 204 = 3876
Step 20: 3876 + 204 = 4080

So, 204*20 = 4080