Sure thing, let's get straight to it. We start with 870 and we're going to multiply it by 61, which means adding 870 to itself 61 times.
Step 1: 0 + 870 = 870
Step 2: 870 + 870 = 1740
Step 3: 1740 + 870 = 2610
Step 4: 2610 + 870 = 3480
Step 5: 3480 + 870 = 4350
Step 6: 4350 + 870 = 5220
Step 7: 5220 + 870 = 6090
Step 8: 6090 + 870 = 6960
Step 9: 6960 + 870 = 7830
Step 10: 7830 + 870 = 8700
Step 11: 8700 + 870 = 9570
Step 12: 9570 + 870 = 10440
Step 13: 10440 + 870 = 11310
Step 14: 11310 + 870 = 12180
Step 15: 12180 + 870 = 13050
Step 16: 13050 + 870 = 13920
Step 17: 13920 + 870 = 14790
Step 18: 14790 + 870 = 15660
Step 19: 15660 + 870 = 16530
Step 20: 16530 + 870 = 17400
Step 21: 17400 + 870 = 18270
Step 22: 18270 + 870 = 19140
Step 23: 19140 + 870 = 20010
Step 24: 20010 + 870 = 20880
Step 25: 20880 + 870 = 21750
Step 26: 21750 + 870 = 22620
Step 27: 22620 + 870 = 23490
Step 28: 23490 + 870 = 24360
Step 29: 24360 + 870 = 25230
Step 30: 25230 + 870 = 26100
Step 31: 26100 + 870 = 26970
Step 32: 26970 + 870 = 27840
Step 33: 27840 + 870 = 28710
Step 34: 28710 + 870 = 29580
Step 35: 29580 + 870 = 30450
Step 36: 30450 + 870 = 31320
Step 37: 31320 + 870 = 32190
Step 38: 32190 + 870 = 33060
Step 39: 33060 + 870 = 33930
Step 40: 33930 + 870 = 34800
Step 41: 34800 + 870 = 35670
Step 42: 35670 + 870 = 36540
Step 43: 36540 + 870 = 37410
Step 44: 37410 + 870 = 38280
Step 45: 38280 + 870 = 39150
Step 46: 39150 + 870 = 40020
Step 47: 40020 + 870 = 40890
Step 48: 40890 + 870 = 41760
Step 49: 41760 + 870 = 42630
Step 50: 42630 + 870 = 43500
Step 51: 43500 + 870 = 44370
Step 52: 44370 + 870 = 45240
Step 53: 45240 + 870 = 46110
Step 54: 46110 + 870 = 46980
Step 55: 46980 + 870 = 47850
Step 56: 47850 + 870 = 48720
Step 57: 48720 + 870 = 49590
Step 58: 49590 + 870 = 50460
Step 59: 50460 + 870 = 51330
Step 60: 51330 + 870 = 52200
Step 61: 52200 + 870 = 53070

So, 870*61 = 53070