Chemical energetics: explain question

When $\ce{Na2SO4}$ dissolves in water, the enthalpy change of solution, $\Delta H_ ext{sol}$, is $-2.4\,\text{kJ}\,\text{mol}^{-1}$. The lattice energy of $\ce{Na2SO4}$ is $+215\,\text{kJ}\,\text{mol}^{-1}$. A student writes an energy cycle linking $\Delta H_ ext{sol}$, lattice energy and the enthalpy changes of hydration of the ions. Explain what is meant by the enthalpy change of hydration, $\Delta H_ ext{hyd}$, and state whether the hydration of the ions in this example releases or absorbs energy. Explain, in terms of the energy cycle, how the numerical value of the enthalpy change of solution is related to the lattice energy and the enthalpy changes of hydration.