Let's get this math done. We have 428 and we're going to multiply it by 20. This is the same as taking 428 and adding it to itself 20 times.
Step 1: 0 + 428 = 428
Step 2: 428 + 428 = 856
Step 3: 856 + 428 = 1284
Step 4: 1284 + 428 = 1712
Step 5: 1712 + 428 = 2140
Step 6: 2140 + 428 = 2568
Step 7: 2568 + 428 = 2996
Step 8: 2996 + 428 = 3424
Step 9: 3424 + 428 = 3852
Step 10: 3852 + 428 = 4280
Step 11: 4280 + 428 = 4708
Step 12: 4708 + 428 = 5136
Step 13: 5136 + 428 = 5564
Step 14: 5564 + 428 = 5992
Step 15: 5992 + 428 = 6420
Step 16: 6420 + 428 = 6848
Step 17: 6848 + 428 = 7276
Step 18: 7276 + 428 = 7704
Step 19: 7704 + 428 = 8132
Step 20: 8132 + 428 = 8560

So, 428*20 = 8560