Sure thing, let's get straight to it. We start with 78 and we're going to multiply it by 86, which means adding 78 to itself 86 times.
Step 1: 0 + 78 = 78
Step 2: 78 + 78 = 156
Step 3: 156 + 78 = 234
Step 4: 234 + 78 = 312
Step 5: 312 + 78 = 390
Step 6: 390 + 78 = 468
Step 7: 468 + 78 = 546
Step 8: 546 + 78 = 624
Step 9: 624 + 78 = 702
Step 10: 702 + 78 = 780
Step 11: 780 + 78 = 858
Step 12: 858 + 78 = 936
Step 13: 936 + 78 = 1014
Step 14: 1014 + 78 = 1092
Step 15: 1092 + 78 = 1170
Step 16: 1170 + 78 = 1248
Step 17: 1248 + 78 = 1326
Step 18: 1326 + 78 = 1404
Step 19: 1404 + 78 = 1482
Step 20: 1482 + 78 = 1560
Step 21: 1560 + 78 = 1638
Step 22: 1638 + 78 = 1716
Step 23: 1716 + 78 = 1794
Step 24: 1794 + 78 = 1872
Step 25: 1872 + 78 = 1950
Step 26: 1950 + 78 = 2028
Step 27: 2028 + 78 = 2106
Step 28: 2106 + 78 = 2184
Step 29: 2184 + 78 = 2262
Step 30: 2262 + 78 = 2340
Step 31: 2340 + 78 = 2418
Step 32: 2418 + 78 = 2496
Step 33: 2496 + 78 = 2574
Step 34: 2574 + 78 = 2652
Step 35: 2652 + 78 = 2730
Step 36: 2730 + 78 = 2808
Step 37: 2808 + 78 = 2886
Step 38: 2886 + 78 = 2964
Step 39: 2964 + 78 = 3042
Step 40: 3042 + 78 = 3120
Step 41: 3120 + 78 = 3198
Step 42: 3198 + 78 = 3276
Step 43: 3276 + 78 = 3354
Step 44: 3354 + 78 = 3432
Step 45: 3432 + 78 = 3510
Step 46: 3510 + 78 = 3588
Step 47: 3588 + 78 = 3666
Step 48: 3666 + 78 = 3744
Step 49: 3744 + 78 = 3822
Step 50: 3822 + 78 = 3900
Step 51: 3900 + 78 = 3978
Step 52: 3978 + 78 = 4056
Step 53: 4056 + 78 = 4134
Step 54: 4134 + 78 = 4212
Step 55: 4212 + 78 = 4290
Step 56: 4290 + 78 = 4368
Step 57: 4368 + 78 = 4446
Step 58: 4446 + 78 = 4524
Step 59: 4524 + 78 = 4602
Step 60: 4602 + 78 = 4680
Step 61: 4680 + 78 = 4758
Step 62: 4758 + 78 = 4836
Step 63: 4836 + 78 = 4914
Step 64: 4914 + 78 = 4992
Step 65: 4992 + 78 = 5070
Step 66: 5070 + 78 = 5148
Step 67: 5148 + 78 = 5226
Step 68: 5226 + 78 = 5304
Step 69: 5304 + 78 = 5382
Step 70: 5382 + 78 = 5460
Step 71: 5460 + 78 = 5538
Step 72: 5538 + 78 = 5616
Step 73: 5616 + 78 = 5694
Step 74: 5694 + 78 = 5772
Step 75: 5772 + 78 = 5850
Step 76: 5850 + 78 = 5928
Step 77: 5928 + 78 = 6006
Step 78: 6006 + 78 = 6084
Step 79: 6084 + 78 = 6162
Step 80: 6162 + 78 = 6240
Step 81: 6240 + 78 = 6318
Step 82: 6318 + 78 = 6396
Step 83: 6396 + 78 = 6474
Step 84: 6474 + 78 = 6552
Step 85: 6552 + 78 = 6630
Step 86: 6630 + 78 = 6708

So, 78*86 = 6708