OK, let's work through this together. We're starting with 526 and we're going to multiply it by 20, which means we add 526 to itself 20 times.
Step 1: 0 + 526 = 526
Step 2: 526 + 526 = 1052
Step 3: 1052 + 526 = 1578
Step 4: 1578 + 526 = 2104
Step 5: 2104 + 526 = 2630
Step 6: 2630 + 526 = 3156
Step 7: 3156 + 526 = 3682
Step 8: 3682 + 526 = 4208
Step 9: 4208 + 526 = 4734
Step 10: 4734 + 526 = 5260
Step 11: 5260 + 526 = 5786
Step 12: 5786 + 526 = 6312
Step 13: 6312 + 526 = 6838
Step 14: 6838 + 526 = 7364
Step 15: 7364 + 526 = 7890
Step 16: 7890 + 526 = 8416
Step 17: 8416 + 526 = 8942
Step 18: 8942 + 526 = 9468
Step 19: 9468 + 526 = 9994
Step 20: 9994 + 526 = 10520

So, 526*20 = 10520