OK, let's work through this together. We're starting with 258 and we're going to multiply it by 14, which means we add 258 to itself 14 times.
Step 1: 0 + 258 = 258
Step 2: 258 + 258 = 516
Step 3: 516 + 258 = 774
Step 4: 774 + 258 = 1032
Step 5: 1032 + 258 = 1290
Step 6: 1290 + 258 = 1548
Step 7: 1548 + 258 = 1806
Step 8: 1806 + 258 = 2064
Step 9: 2064 + 258 = 2322
Step 10: 2322 + 258 = 2580
Step 11: 2580 + 258 = 2838
Step 12: 2838 + 258 = 3096
Step 13: 3096 + 258 = 3354
Step 14: 3354 + 258 = 3612

So, 258*14 = 3612