5. Papa, Masha, and Yasha are going to school. While Papa takes 3 steps, Masha takes 5 steps. While Masha takes 3 steps, Yasha takes 5 steps. Masha and Yasha counted that together they made 400 steps. How many steps did Papa take?
Answer: 90 steps.

Solution. 1st method. Let's call the distance equal to 3 steps of Masha and 5 steps of Yasha a Giant's step. While the Giant makes one step, Masha and Yasha together make 8 steps. Since they made 400 steps together, the Giant would have made 400:8=50 giant steps in this time. If the Giant made 50 steps, then Masha made 150 steps. Now let's count them in "fives." 150 is 30 times 5 steps. This means that the father made 30 times 3 steps, that is, 90 steps.

2nd method. While Masha makes 3$\cdot$5=15 steps, the father makes $3 \cdot 3=9$ steps, and Yasha makes $5 \cdot 5=25$ steps. Together, in this time, Masha and Yasha will make $15+25=40$ steps. And while they make 400 steps, the father will also make 10 times more steps, that is, 9$\cdot$10=90 steps.

## 5th grade. Recommendations for checking.

Each problem is scored out of 7 points. Each score is an integer from 0 to 7. Some guidelines for checking are provided below. Naturally, the creators cannot foresee all cases. When evaluating a solution, it is important to determine whether the provided solution is generally correct (although it may have flaws) - in which case the solution should be scored no less than 4 points. Or if it is incorrect (although it may have significant progress) - in which case the score should not exceed 3 points.