I need help can someone help? Please

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.

Sunday: 1 1 2 monday: 1 tuesday: 2 1 2 wednesday: 1 3 4 thursday: 2 friday: 1 1 2 saturday: 2 jenna is a swimmer and trains every day. the schedule shown outlines the number of hours she trains each day. what is the total number of hours that jenna trains during the week?

Find the volume of the solid bounded by the plane z=0 and the paraboloid z=1-x^2 –y^2