OK, let's work through this together. We're starting with 964 and we're going to multiply it by 20, which means we add 964 to itself 20 times.
Step 1: 0 + 964 = 964
Step 2: 964 + 964 = 1928
Step 3: 1928 + 964 = 2892
Step 4: 2892 + 964 = 3856
Step 5: 3856 + 964 = 4820
Step 6: 4820 + 964 = 5784
Step 7: 5784 + 964 = 6748
Step 8: 6748 + 964 = 7712
Step 9: 7712 + 964 = 8676
Step 10: 8676 + 964 = 9640
Step 11: 9640 + 964 = 10604
Step 12: 10604 + 964 = 11568
Step 13: 11568 + 964 = 12532
Step 14: 12532 + 964 = 13496
Step 15: 13496 + 964 = 14460
Step 16: 14460 + 964 = 15424
Step 17: 15424 + 964 = 16388
Step 18: 16388 + 964 = 17352
Step 19: 17352 + 964 = 18316
Step 20: 18316 + 964 = 19280

So, 964*20 = 19280