OK, let's crack this. We're given 149 and our task is to multiply it by 15. Essentially, we'll be adding 149 to itself 15 times.
Step 1: 0 + 149 = 149
Step 2: 149 + 149 = 298
Step 3: 298 + 149 = 447
Step 4: 447 + 149 = 596
Step 5: 596 + 149 = 745
Step 6: 745 + 149 = 894
Step 7: 894 + 149 = 1043
Step 8: 1043 + 149 = 1192
Step 9: 1192 + 149 = 1341
Step 10: 1341 + 149 = 1490
Step 11: 1490 + 149 = 1639
Step 12: 1639 + 149 = 1788
Step 13: 1788 + 149 = 1937
Step 14: 1937 + 149 = 2086
Step 15: 2086 + 149 = 2235

So, 149*15 = 2235