Uranus and Neptune have rings and many moons and are part of a group called the planets

They are called the outer planets or part of the outer planets

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen

Since wxyz is 4, halfof that would be 2.