Sure thing, let's get straight to it. We start with 225 and we're going to multiply it by 20, which means adding 225 to itself 20 times.
Step 1: 0 + 225 = 225
Step 2: 225 + 225 = 450
Step 3: 450 + 225 = 675
Step 4: 675 + 225 = 900
Step 5: 900 + 225 = 1125
Step 6: 1125 + 225 = 1350
Step 7: 1350 + 225 = 1575
Step 8: 1575 + 225 = 1800
Step 9: 1800 + 225 = 2025
Step 10: 2025 + 225 = 2250
Step 11: 2250 + 225 = 2475
Step 12: 2475 + 225 = 2700
Step 13: 2700 + 225 = 2925
Step 14: 2925 + 225 = 3150
Step 15: 3150 + 225 = 3375
Step 16: 3375 + 225 = 3600
Step 17: 3600 + 225 = 3825
Step 18: 3825 + 225 = 4050
Step 19: 4050 + 225 = 4275
Step 20: 4275 + 225 = 4500

So, 225*20 = 4500