OK, let's work through this together. We're starting with 280 and we're going to multiply it by 10, which means we add 280 to itself 10 times.
Step 1: 0 + 280 = 280
Step 2: 280 + 280 = 560
Step 3: 560 + 280 = 840
Step 4: 840 + 280 = 1120
Step 5: 1120 + 280 = 1400
Step 6: 1400 + 280 = 1680
Step 7: 1680 + 280 = 1960
Step 8: 1960 + 280 = 2240
Step 9: 2240 + 280 = 2520
Step 10: 2520 + 280 = 2800

So, 280*10 = 2800