Ca(s)+mgso4(aq)-> caso4(aq)+mg
bacl2(aq)+k2so4(aq)-> baso4(s)+2kcl
rewrite each reaction as a balanced net ionic equation.

First equation

1) Write the balanced equation

Ca(s)+MgSO4(AQ)->CaSO4(aq)+Mg

2) Write the ionic equatin showing the oxidation states (charges), next to each ion

Ca (0) + Mg (2+) + SO4 (2-) ---> Ca (2+) + SO4 (2-) + Mg (0)

3) Remove the spectator ions (those that appear exactly the same at both sides). In this case remove SO4 (2-) from both sides to get:

Net ionic equation
Ca(0) + Mg(2+) ---> Ca(2+) + Mg(0)

Now go with the second equation

1) Write the balanced equation

BaCl2(aq)+K2SO4(aq)->BaSO4(s)+2KCl

2) Write the ionic equation

Ba (2+) + 2Cl (1-) + 2K (1+) +SO4 (2-) ---> Ba(2+) + SO4 (2-) + 2 K(1+) + 2Cl(1-)

3) Remove the spectator ions.

Here all the ions are spectator, because non of them changed the oxidation state. Then,  there is not net ionic equation.