OK, let's work through this together. We're starting with 807 and we're going to multiply it by 24, which means we add 807 to itself 24 times.
Step 1: 0 + 807 = 807
Step 2: 807 + 807 = 1614
Step 3: 1614 + 807 = 2421
Step 4: 2421 + 807 = 3228
Step 5: 3228 + 807 = 4035
Step 6: 4035 + 807 = 4842
Step 7: 4842 + 807 = 5649
Step 8: 5649 + 807 = 6456
Step 9: 6456 + 807 = 7263
Step 10: 7263 + 807 = 8070
Step 11: 8070 + 807 = 8877
Step 12: 8877 + 807 = 9684
Step 13: 9684 + 807 = 10491
Step 14: 10491 + 807 = 11298
Step 15: 11298 + 807 = 12105
Step 16: 12105 + 807 = 12912
Step 17: 12912 + 807 = 13719
Step 18: 13719 + 807 = 14526
Step 19: 14526 + 807 = 15333
Step 20: 15333 + 807 = 16140
Step 21: 16140 + 807 = 16947
Step 22: 16947 + 807 = 17754
Step 23: 17754 + 807 = 18561
Step 24: 18561 + 807 = 19368

So, 807*24 = 19368