OK, let's work through this together. We're starting with 650 and we're going to multiply it by 20, which means we add 650 to itself 20 times.
Step 1: 0 + 650 = 650
Step 2: 650 + 650 = 1300
Step 3: 1300 + 650 = 1950
Step 4: 1950 + 650 = 2600
Step 5: 2600 + 650 = 3250
Step 6: 3250 + 650 = 3900
Step 7: 3900 + 650 = 4550
Step 8: 4550 + 650 = 5200
Step 9: 5200 + 650 = 5850
Step 10: 5850 + 650 = 6500
Step 11: 6500 + 650 = 7150
Step 12: 7150 + 650 = 7800
Step 13: 7800 + 650 = 8450
Step 14: 8450 + 650 = 9100
Step 15: 9100 + 650 = 9750
Step 16: 9750 + 650 = 10400
Step 17: 10400 + 650 = 11050
Step 18: 11050 + 650 = 11700
Step 19: 11700 + 650 = 12350
Step 20: 12350 + 650 = 13000

So, 650*20 = 13000