Age Problems

1. 1Time PassesBoth the father and the child gain exactly 4 years. Watch both bars grow by the same orange piece.+4 years for each person
2. 2The Gap Never ChangesIn the future the total is 44 and the father is still exactly 24 years older — because both people aged by the same amount.Total: 44; Difference: 24
3. 3A Familiar ProblemAt this moment in the future we know a sum and a difference — this is exactly the sum-and-difference problem we already know how to solve.Sum 44, difference 24
4. 4Peel Off the Extra PieceMove the father’s extra 24 years aside. What remains of his bar is exactly as long as the child’s bar.44 − 24 = 20
5. 5The Child’s Age in the FutureHalve what remains to find the child’s age in 4 years. The father’s future age is one gap more.(44 − 24) ÷ 2 = 10
6. 6Travel Back to TodayGo back 4 years: each person loses exactly 4 years.Child: 10 − 4 = 6; Father: 34 − 4 = 30
7. 7Check and the Golden RuleCheck today: 30 + 6 = 36 years in total, and 30 − 6 = 24 years apart. In the future the total grows to 44 while the gap stays 24.30 + 6 = 36 ✓

Change the numbers to test the engine with any sum & difference problem: