Let's get this math done. We have 510 and we're going to multiply it by 31. This is the same as taking 510 and adding it to itself 31 times.
Step 1: 0 + 510 = 510
Step 2: 510 + 510 = 1020
Step 3: 1020 + 510 = 1530
Step 4: 1530 + 510 = 2040
Step 5: 2040 + 510 = 2550
Step 6: 2550 + 510 = 3060
Step 7: 3060 + 510 = 3570
Step 8: 3570 + 510 = 4080
Step 9: 4080 + 510 = 4590
Step 10: 4590 + 510 = 5100
Step 11: 5100 + 510 = 5610
Step 12: 5610 + 510 = 6120
Step 13: 6120 + 510 = 6630
Step 14: 6630 + 510 = 7140
Step 15: 7140 + 510 = 7650
Step 16: 7650 + 510 = 8160
Step 17: 8160 + 510 = 8670
Step 18: 8670 + 510 = 9180
Step 19: 9180 + 510 = 9690
Step 20: 9690 + 510 = 10200
Step 21: 10200 + 510 = 10710
Step 22: 10710 + 510 = 11220
Step 23: 11220 + 510 = 11730
Step 24: 11730 + 510 = 12240
Step 25: 12240 + 510 = 12750
Step 26: 12750 + 510 = 13260
Step 27: 13260 + 510 = 13770
Step 28: 13770 + 510 = 14280
Step 29: 14280 + 510 = 14790
Step 30: 14790 + 510 = 15300
Step 31: 15300 + 510 = 15810

So, 510*31 = 15810