Alright, let's solve this math problem step by step. First, we have the number 407. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 90. So, we're going to take the number 407 and add it to itself 90 times.
Step 1: 0 + 407 = 407
Step 2: 407 + 407 = 814
Step 3: 814 + 407 = 1221
Step 4: 1221 + 407 = 1628
Step 5: 1628 + 407 = 2035
Step 6: 2035 + 407 = 2442
Step 7: 2442 + 407 = 2849
Step 8: 2849 + 407 = 3256
Step 9: 3256 + 407 = 3663
Step 10: 3663 + 407 = 4070
Step 11: 4070 + 407 = 4477
Step 12: 4477 + 407 = 4884
Step 13: 4884 + 407 = 5291
Step 14: 5291 + 407 = 5698
Step 15: 5698 + 407 = 6105
Step 16: 6105 + 407 = 6512
Step 17: 6512 + 407 = 6919
Step 18: 6919 + 407 = 7326
Step 19: 7326 + 407 = 7733
Step 20: 7733 + 407 = 8140
Step 21: 8140 + 407 = 8547
Step 22: 8547 + 407 = 8954
Step 23: 8954 + 407 = 9361
Step 24: 9361 + 407 = 9768
Step 25: 9768 + 407 = 10175
Step 26: 10175 + 407 = 10582
Step 27: 10582 + 407 = 10989
Step 28: 10989 + 407 = 11396
Step 29: 11396 + 407 = 11803
Step 30: 11803 + 407 = 12210
Step 31: 12210 + 407 = 12617
Step 32: 12617 + 407 = 13024
Step 33: 13024 + 407 = 13431
Step 34: 13431 + 407 = 13838
Step 35: 13838 + 407 = 14245
Step 36: 14245 + 407 = 14652
Step 37: 14652 + 407 = 15059
Step 38: 15059 + 407 = 15466
Step 39: 15466 + 407 = 15873
Step 40: 15873 + 407 = 16280
Step 41: 16280 + 407 = 16687
Step 42: 16687 + 407 = 17094
Step 43: 17094 + 407 = 17501
Step 44: 17501 + 407 = 17908
Step 45: 17908 + 407 = 18315
Step 46: 18315 + 407 = 18722
Step 47: 18722 + 407 = 19129
Step 48: 19129 + 407 = 19536
Step 49: 19536 + 407 = 19943
Step 50: 19943 + 407 = 20350
Step 51: 20350 + 407 = 20757
Step 52: 20757 + 407 = 21164
Step 53: 21164 + 407 = 21571
Step 54: 21571 + 407 = 21978
Step 55: 21978 + 407 = 22385
Step 56: 22385 + 407 = 22792
Step 57: 22792 + 407 = 23199
Step 58: 23199 + 407 = 23606
Step 59: 23606 + 407 = 24013
Step 60: 24013 + 407 = 24420
Step 61: 24420 + 407 = 24827
Step 62: 24827 + 407 = 25234
Step 63: 25234 + 407 = 25641
Step 64: 25641 + 407 = 26048
Step 65: 26048 + 407 = 26455
Step 66: 26455 + 407 = 26862
Step 67: 26862 + 407 = 27269
Step 68: 27269 + 407 = 27676
Step 69: 27676 + 407 = 28083
Step 70: 28083 + 407 = 28490
Step 71: 28490 + 407 = 28897
Step 72: 28897 + 407 = 29304
Step 73: 29304 + 407 = 29711
Step 74: 29711 + 407 = 30118
Step 75: 30118 + 407 = 30525
Step 76: 30525 + 407 = 30932
Step 77: 30932 + 407 = 31339
Step 78: 31339 + 407 = 31746
Step 79: 31746 + 407 = 32153
Step 80: 32153 + 407 = 32560
Step 81: 32560 + 407 = 32967
Step 82: 32967 + 407 = 33374
Step 83: 33374 + 407 = 33781
Step 84: 33781 + 407 = 34188
Step 85: 34188 + 407 = 34595
Step 86: 34595 + 407 = 35002
Step 87: 35002 + 407 = 35409
Step 88: 35409 + 407 = 35816
Step 89: 35816 + 407 = 36223
Step 90: 36223 + 407 = 36630

So, 407*90 = 36630