OK, let's work through this together. We're starting with 890 and we're going to multiply it by 10, which means we add 890 to itself 10 times.
Step 1: 0 + 890 = 890
Step 2: 890 + 890 = 1780
Step 3: 1780 + 890 = 2670
Step 4: 2670 + 890 = 3560
Step 5: 3560 + 890 = 4450
Step 6: 4450 + 890 = 5340
Step 7: 5340 + 890 = 6230
Step 8: 6230 + 890 = 7120
Step 9: 7120 + 890 = 8010
Step 10: 8010 + 890 = 8900

So, 890*10 = 8900