Let's get this math done. We have 143 and we're going to multiply it by 15. This is the same as taking 143 and adding it to itself 15 times.
Step 1: 0 + 143 = 143
Step 2: 143 + 143 = 286
Step 3: 286 + 143 = 429
Step 4: 429 + 143 = 572
Step 5: 572 + 143 = 715
Step 6: 715 + 143 = 858
Step 7: 858 + 143 = 1001
Step 8: 1001 + 143 = 1144
Step 9: 1144 + 143 = 1287
Step 10: 1287 + 143 = 1430
Step 11: 1430 + 143 = 1573
Step 12: 1573 + 143 = 1716
Step 13: 1716 + 143 = 1859
Step 14: 1859 + 143 = 2002
Step 15: 2002 + 143 = 2145

So, 143*15 = 2145