1. **State the problem:** We are given that the sum of a father's and his son's current ages is 56. Four years ago, the father was four times as old as the son. We need to find their current ages. 2. **Define variables:** Let the son's current age be $x$ years. Then the father's current age is $56 - x$ years (since their sum is 56). 3. **Express past ages:** Four years ago, the son was $x - 4$ years old. Four years ago, the father was $(56 - x) - 4 = 52 - x$ years old. 4. **Formulate equation based on given condition:** Four years ago, the father was four times as old as the son, so: $$52 - x = 4(x - 4)$$ 5. **Solve the equation:** Expand the right side: $$52 - x = 4x - 16$$ Bring all terms to one side: $$52 + 16 = 4x + x$$ $$68 = 5x$$ Divide both sides by 5: $$x = \frac{68}{5} = 13.6$$ 6. **Find father's current age:** $$56 - x = 56 - 13.6 = 42.4$$ 7. **Conclusion:** The son's current age is $13.6$ years. The father's current age is $42.4$ years.