Here $$16060666$$ and $$16007777$$ are $$8-$$digits numbers in which the same numbers $$1, 6$$ and $$0$$ are placed at crores, ten lakhs and lakhs respectively whereas $$6$$ and $$0$$ are placed at ten thousands place respectively.
Since $$6 > 0$$
Therefore $$16060666 > 16007777$$
$$1808088$$ and $$1808090$$ are both $$7-$$digits numbers in which the same numbers $$1, 8, 0, 8$$ and o are placed at ten lakhs, lakhs, ten thousands, thousands and hundreds places respectively whereas $$9$$ and $$8$$ are placed at tens place respectively
Since $$9 > 8$$
Therefore $$1808090 > 1808088$$
$$190909$$ and $$181888$$ are both $$6-$$digits numbers
In both the numbers the same digit $$1$$ is at lakhs place and the digits at ten thousands place are $$9$$ and $$8$$
Since $$9 > 8$$
Therefore $$190909 > 181888$$
The given numbers in the descending order are:
$$16060666 > 16007777 > 1808090 > 1808088 > 190909 > 181888$$