Question

На одном уроке ученики сделали 30 игрушек, а на другом 20 игрушек.Затем 10 игрушек они подарили малышам.Сколько игрушек осталось у учеников? Реши задачу разными способами и объясни решения.

Answer 1

30+20-10=40
30-10+20=40
20-10+30=40

Answer 2

30+20=50-10=40
20-10=10+30=40

Answer 3

Problem Analysis

The problem states that students made 30 toys in one lesson and 20 toys in another lesson. Then they gave 10 toys to babies. We need to determine how many toys are left with the students.

Solution 1: Subtraction

We can solve this problem by subtracting the number of toys given to the babies from the total number of toys made by the students.

1. The students made 30 toys in one lesson and 20 toys in another lesson. 2. The total number of toys made by the students is 30 + 20 = 50 toys. 3. The students gave 10 toys to the babies. 4. To find the number of toys left with the students, we subtract the number of toys given to the babies from the total number of toys made by the students: 50 - 10 = 40 toys.

Therefore, there are 40 toys left with the students.

Solution 2: Addition and Subtraction

Another way to solve this problem is by adding the number of toys made in both lessons and then subtracting the number of toys given to the babies.

1. The students made 30 toys in one lesson and 20 toys in another lesson. 2. To find the total number of toys made by the students, we add the number of toys made in both lessons: 30 + 20 = 50 toys. 3. The students gave 10 toys to the babies. 4. To find the number of toys left with the students, we subtract the number of toys given to the babies from the total number of toys made by the students: 50 - 10 = 40 toys.

Therefore, there are 40 toys left with the students.

Solution 3: Using Variables

We can also solve this problem using variables to represent the number of toys made in each lesson and the number of toys given to the babies.

Let's assume: - The number of toys made in the first lesson is x. - The number of toys made in the second lesson is y. - The number of toys given to the babies is z.

1. The students made 30 toys in one lesson, so we can write the equation: x = 30. 2. The students made 20 toys in another lesson, so we can write the equation: y = 20. 3. The students gave 10 toys to the babies, so we can write the equation: z = 10. 4. To find the number of toys left with the students, we subtract the number of toys given to the babies from the total number of toys made by the students: x + y - z.

Substituting the given values, we have: 30 + 20 - 10 = 40 toys.

Therefore, there are 40 toys left with the students.

Conclusion

In conclusion, the students have 40 toys left after making 30 toys in one lesson, 20 toys in another lesson, and giving 10 toys to the babies. This can be solved by subtraction, addition and subtraction, or using variables to represent the quantities.