OK, let's work through this together. We're starting with 20 and we're going to multiply it by 49, which means we add 20 to itself 49 times.
Step 1: 0 + 20 = 20
Step 2: 20 + 20 = 40
Step 3: 40 + 20 = 60
Step 4: 60 + 20 = 80
Step 5: 80 + 20 = 100
Step 6: 100 + 20 = 120
Step 7: 120 + 20 = 140
Step 8: 140 + 20 = 160
Step 9: 160 + 20 = 180
Step 10: 180 + 20 = 200
Step 11: 200 + 20 = 220
Step 12: 220 + 20 = 240
Step 13: 240 + 20 = 260
Step 14: 260 + 20 = 280
Step 15: 280 + 20 = 300
Step 16: 300 + 20 = 320
Step 17: 320 + 20 = 340
Step 18: 340 + 20 = 360
Step 19: 360 + 20 = 380
Step 20: 380 + 20 = 400
Step 21: 400 + 20 = 420
Step 22: 420 + 20 = 440
Step 23: 440 + 20 = 460
Step 24: 460 + 20 = 480
Step 25: 480 + 20 = 500
Step 26: 500 + 20 = 520
Step 27: 520 + 20 = 540
Step 28: 540 + 20 = 560
Step 29: 560 + 20 = 580
Step 30: 580 + 20 = 600
Step 31: 600 + 20 = 620
Step 32: 620 + 20 = 640
Step 33: 640 + 20 = 660
Step 34: 660 + 20 = 680
Step 35: 680 + 20 = 700
Step 36: 700 + 20 = 720
Step 37: 720 + 20 = 740
Step 38: 740 + 20 = 760
Step 39: 760 + 20 = 780
Step 40: 780 + 20 = 800
Step 41: 800 + 20 = 820
Step 42: 820 + 20 = 840
Step 43: 840 + 20 = 860
Step 44: 860 + 20 = 880
Step 45: 880 + 20 = 900
Step 46: 900 + 20 = 920
Step 47: 920 + 20 = 940
Step 48: 940 + 20 = 960
Step 49: 960 + 20 = 980

So, 20*49 = 980