Adding difficulty is the wide range of estimates for live mass.

I've been doing that for decades; it adds difficulty and fun.

"Well, that seems to add little extra difficulty to an already impossible task."

Heavy bots will appear in levels to add difficulty to gameplay.

In the end, these adjustments proved to add difficulty to the operation.

Water hazards, like bunkers, are natural obstacles designed to add both beauty and difficulty to a golf course.

Some ellipticals have magnetic resistance controls that add difficulty to doing the motion.

She began adding difficulty on the fly, but could not get away with it cleanly.

Jumps may also be performed with variations in the arm positions in the air to add difficulty.

And we are still trying to add difficulty to her programme".