Let's roll up our sleeves and solve this. We have 834 and we're going to multiply it by 12, essentially adding 834 to itself 12 times.
Step 1: 0 + 834 = 834
Step 2: 834 + 834 = 1668
Step 3: 1668 + 834 = 2502
Step 4: 2502 + 834 = 3336
Step 5: 3336 + 834 = 4170
Step 6: 4170 + 834 = 5004
Step 7: 5004 + 834 = 5838
Step 8: 5838 + 834 = 6672
Step 9: 6672 + 834 = 7506
Step 10: 7506 + 834 = 8340
Step 11: 8340 + 834 = 9174
Step 12: 9174 + 834 = 10008

So, 834*12 = 10008