One mole of CaCl2 contains 1 mole of calcium.
Therefore, 0.3 moles of CaCl2 will contain 0.3 moles of calcium.
1 mole of calcium contains Avogadro's number of ions, therefore, 0.3 moles will contain:
number of ions = 0.3 * 6.02 * 10^23 = 1.806 * 10^23 ions