OK, let's crack this. We're given 158 and our task is to multiply it by 61. Essentially, we'll be adding 158 to itself 61 times.
Step 1: 0 + 158 = 158
Step 2: 158 + 158 = 316
Step 3: 316 + 158 = 474
Step 4: 474 + 158 = 632
Step 5: 632 + 158 = 790
Step 6: 790 + 158 = 948
Step 7: 948 + 158 = 1106
Step 8: 1106 + 158 = 1264
Step 9: 1264 + 158 = 1422
Step 10: 1422 + 158 = 1580
Step 11: 1580 + 158 = 1738
Step 12: 1738 + 158 = 1896
Step 13: 1896 + 158 = 2054
Step 14: 2054 + 158 = 2212
Step 15: 2212 + 158 = 2370
Step 16: 2370 + 158 = 2528
Step 17: 2528 + 158 = 2686
Step 18: 2686 + 158 = 2844
Step 19: 2844 + 158 = 3002
Step 20: 3002 + 158 = 3160
Step 21: 3160 + 158 = 3318
Step 22: 3318 + 158 = 3476
Step 23: 3476 + 158 = 3634
Step 24: 3634 + 158 = 3792
Step 25: 3792 + 158 = 3950
Step 26: 3950 + 158 = 4108
Step 27: 4108 + 158 = 4266
Step 28: 4266 + 158 = 4424
Step 29: 4424 + 158 = 4582
Step 30: 4582 + 158 = 4740
Step 31: 4740 + 158 = 4898
Step 32: 4898 + 158 = 5056
Step 33: 5056 + 158 = 5214
Step 34: 5214 + 158 = 5372
Step 35: 5372 + 158 = 5530
Step 36: 5530 + 158 = 5688
Step 37: 5688 + 158 = 5846
Step 38: 5846 + 158 = 6004
Step 39: 6004 + 158 = 6162
Step 40: 6162 + 158 = 6320
Step 41: 6320 + 158 = 6478
Step 42: 6478 + 158 = 6636
Step 43: 6636 + 158 = 6794
Step 44: 6794 + 158 = 6952
Step 45: 6952 + 158 = 7110
Step 46: 7110 + 158 = 7268
Step 47: 7268 + 158 = 7426
Step 48: 7426 + 158 = 7584
Step 49: 7584 + 158 = 7742
Step 50: 7742 + 158 = 7900
Step 51: 7900 + 158 = 8058
Step 52: 8058 + 158 = 8216
Step 53: 8216 + 158 = 8374
Step 54: 8374 + 158 = 8532
Step 55: 8532 + 158 = 8690
Step 56: 8690 + 158 = 8848
Step 57: 8848 + 158 = 9006
Step 58: 9006 + 158 = 9164
Step 59: 9164 + 158 = 9322
Step 60: 9322 + 158 = 9480
Step 61: 9480 + 158 = 9638

So, 158*61 = 9638