OK, let's work through this together. We're starting with 890 and we're going to multiply it by 50, which means we add 890 to itself 50 times.
Step 1: 0 + 890 = 890
Step 2: 890 + 890 = 1780
Step 3: 1780 + 890 = 2670
Step 4: 2670 + 890 = 3560
Step 5: 3560 + 890 = 4450
Step 6: 4450 + 890 = 5340
Step 7: 5340 + 890 = 6230
Step 8: 6230 + 890 = 7120
Step 9: 7120 + 890 = 8010
Step 10: 8010 + 890 = 8900
Step 11: 8900 + 890 = 9790
Step 12: 9790 + 890 = 10680
Step 13: 10680 + 890 = 11570
Step 14: 11570 + 890 = 12460
Step 15: 12460 + 890 = 13350
Step 16: 13350 + 890 = 14240
Step 17: 14240 + 890 = 15130
Step 18: 15130 + 890 = 16020
Step 19: 16020 + 890 = 16910
Step 20: 16910 + 890 = 17800
Step 21: 17800 + 890 = 18690
Step 22: 18690 + 890 = 19580
Step 23: 19580 + 890 = 20470
Step 24: 20470 + 890 = 21360
Step 25: 21360 + 890 = 22250
Step 26: 22250 + 890 = 23140
Step 27: 23140 + 890 = 24030
Step 28: 24030 + 890 = 24920
Step 29: 24920 + 890 = 25810
Step 30: 25810 + 890 = 26700
Step 31: 26700 + 890 = 27590
Step 32: 27590 + 890 = 28480
Step 33: 28480 + 890 = 29370
Step 34: 29370 + 890 = 30260
Step 35: 30260 + 890 = 31150
Step 36: 31150 + 890 = 32040
Step 37: 32040 + 890 = 32930
Step 38: 32930 + 890 = 33820
Step 39: 33820 + 890 = 34710
Step 40: 34710 + 890 = 35600
Step 41: 35600 + 890 = 36490
Step 42: 36490 + 890 = 37380
Step 43: 37380 + 890 = 38270
Step 44: 38270 + 890 = 39160
Step 45: 39160 + 890 = 40050
Step 46: 40050 + 890 = 40940
Step 47: 40940 + 890 = 41830
Step 48: 41830 + 890 = 42720
Step 49: 42720 + 890 = 43610
Step 50: 43610 + 890 = 44500

So, 890*50 = 44500