1. Senya thought of two numbers, then subtracted the smaller from the larger, added both numbers and the difference, and got 68. What was the larger of the numbers Senya thought of?
Answer: 34.

Solution. The subtrahend plus the difference equals the minuend. Therefore, the doubled minuend equals 68.

Comment. Correct solution - 20 points. The result is obtained based on examples and the pattern is noticed but not explained - 15 points. The result is obtained based on one example - 10 points. The solution is started, but the progress is insignificant - 1 point. The correct answer is given without explanation - 1 point.