Reduce to simplest form.

-1/2 - 2/5 =

Dylan and dusty plan to take weekly surfing lessons together. if the 2-hour lessons are $20 per person and they plan to spend $100 each on new surfboards, what is the maximum number of lessons the two can take if the total amount spent for lessons and surfboards is at most $480?

Asphere has a diameter of 10 in. what is the volume of the sphere?

What is the measure of the smallest angle in the diagram? 15 29 32 45