OK, let's work through this together. We're starting with 784 and we're going to multiply it by 18, which means we add 784 to itself 18 times.
Step 1: 0 + 784 = 784
Step 2: 784 + 784 = 1568
Step 3: 1568 + 784 = 2352
Step 4: 2352 + 784 = 3136
Step 5: 3136 + 784 = 3920
Step 6: 3920 + 784 = 4704
Step 7: 4704 + 784 = 5488
Step 8: 5488 + 784 = 6272
Step 9: 6272 + 784 = 7056
Step 10: 7056 + 784 = 7840
Step 11: 7840 + 784 = 8624
Step 12: 8624 + 784 = 9408
Step 13: 9408 + 784 = 10192
Step 14: 10192 + 784 = 10976
Step 15: 10976 + 784 = 11760
Step 16: 11760 + 784 = 12544
Step 17: 12544 + 784 = 13328
Step 18: 13328 + 784 = 14112

So, 784*18 = 14112