16км9м+16км991м

To add these two distances together, you need to first convert both distances to the same unit. Let's convert both distances to meters:

16 km 9 m = 16,000 m + 9 m = 16,009 m

16 km 991 m = 16,000 m + 991 m = 16,991 m

Now add the two distances together:

16,009 m + 16,991 m = 33,000 m

Therefore, the sum of 16 km 9 m and 16 km 991 m is 33 kilometers.