Let's get this math done. We have 890 and we're going to multiply it by 23. This is the same as taking 890 and adding it to itself 23 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
Step 11: 8900 + 890 = 9790
Step 12: 9790 + 890 = 10680
Step 13: 10680 + 890 = 11570
Step 14: 11570 + 890 = 12460
Step 15: 12460 + 890 = 13350
Step 16: 13350 + 890 = 14240
Step 17: 14240 + 890 = 15130
Step 18: 15130 + 890 = 16020
Step 19: 16020 + 890 = 16910
Step 20: 16910 + 890 = 17800
Step 21: 17800 + 890 = 18690
Step 22: 18690 + 890 = 19580
Step 23: 19580 + 890 = 20470

So, 890*23 = 20470