Students count and compare student numbers across grades using a pictograph.

Problem Analysis:

The task involves interpreting a pictograph to answer questions about the number of students in different grades at Abcous Elementary. The pictograph uses symbols to represent students, with the key indicating:
- Each full symbol represents 2 people.
- Each half symbol represents 1 person.

We need to count the symbols for each grade and use the key to determine the total number of students in each grade. Then, we will answer the specific questions based on these counts.

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Step-by-Step Solution:

#### 1. Counting Students in Each Grade:

##### 1st Grade:
- There are 4 full symbols.
- Using the key: \( 4 \times 2 = 8 \) students.

##### 2nd Grade:
- There are 3 full symbols and 1 half symbol.
- Using the key: \( (3 \times 2) + 1 = 6 + 1 = 7 \) students.

##### 3rd Grade:
- There are 5 full symbols.
- Using the key: \( 5 \times 2 = 10 \) students.

##### 4th Grade:
- There are 9 full symbols.
- Using the key: \( 9 \times 2 = 18 \) students.

##### 5th Grade:
- There are 7 full symbols and 1 half symbol.
- Using the key: \( (7 \times 2) + 1 = 14 + 1 = 15 \) students.

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#### 2. Answering the Questions:

##### Question 1: How many students are in the 1st grade?
- From the count above: 8 students.

##### Question 2: How many students are in the 5th grade?
- From the count above: 15 students.

##### Question 3: How many more students are in the 2nd grade than the 1st grade?
- Number of students in 2nd grade: 7.
- Number of students in 1st grade: 8.
- Difference: \( 7 - 8 = -1 \).
- Since the question asks "how many more," the answer is 0 (no more students in 2nd grade than in 1st grade).

##### Question 4: How many more students are in the 5th grade than the 3rd grade?
- Number of students in 5th grade: 15.
- Number of students in 3rd grade: 10.
- Difference: \( 15 - 10 = 5 \).
- Answer: 5 more students.

##### Question 5: How many students are there all together in the school?
- Total students = Students in 1st grade + Students in 2nd grade + Students in 3rd grade + Students in 4th grade + Students in 5th grade.
- Total = \( 8 + 7 + 10 + 18 + 15 = 58 \).
- Answer: 58 students.

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Final Answers:

1. 8 students
2. 15 students
3. 0 more students
4. 5 more students
5. 58 students

\boxed{8, 15, 0, 5, 58}