Alright, let's solve this math problem step by step. First, we have the number 426. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 12. So, we're going to take the number 426 and add it to itself 12 times.
Step 1: 0 + 426 = 426
Step 2: 426 + 426 = 852
Step 3: 852 + 426 = 1278
Step 4: 1278 + 426 = 1704
Step 5: 1704 + 426 = 2130
Step 6: 2130 + 426 = 2556
Step 7: 2556 + 426 = 2982
Step 8: 2982 + 426 = 3408
Step 9: 3408 + 426 = 3834
Step 10: 3834 + 426 = 4260
Step 11: 4260 + 426 = 4686
Step 12: 4686 + 426 = 5112

So, 426*12 = 5112