Well, being a weeabo doesn't make you good at math.
there are around 100 yen in 1 US dollar. There are 100 pennies in 1 US dollar. 1/100 = .01, or 1%. Therefore, 1 yen is about 1% of a US dollar.
The hard badge is not that hard if you don't climb too much or use the rocket in the initial ascent. Once you level out your flight, use the rocket occasionally to boost your speed, just make sure you don't send it into the red zone.