The number $10^{12}+10^6+1$ is written out in full. How many of its digits are zeros?

The three powers sit in three different columns, so nothing carries and the number simply reads 1000001000001 — a 1 in the $10^{12}$ column, a 1 in the $10^6$ column and a 1 in the units column, with zeros filling every other place. That is 13 digits in all, three of which are 1s, leaving 10 zeros. The trap 18 adds the 12 zeros of $10^{12}$ to the 6 zeros of $10^6$ and forgets that the smaller number is written INSIDE the bigger one rather than beside it. Answering 12 gives the zeros of $10^{12}$ on its own, before the other two 1s punch holes in the run.