In the image, the focus is on multiple activities labeled Activité 12, Activité 13, Activité 14, and Activité 15, each containing various mathematical exercises.

Here's a breakdown of each activity:

Activité 12:

Deals with integer and natural number operations, particularly focusing on expressing sums and performing arithmetic. The tasks are:

1. $4 + 1 + 6$: Simplification of a sum.
2. Expressing sums: Using natural numbers (e.g., 3 + 2 + 4 + 3).
3. Conjecture formation: Generalizing based on specific sums.

Activité 13:

1. Expression of numbers: Here, 758964578 and other large numbers are broken down.
2. Patterns in sums: Finding sums such as $7 + 7 = 8$, $11 + 11 = 12$.
3. Generalization: Exploring if such results can be generalized.

Activité 14:

Focuses on comparing numbers and investigating if products form perfect squares.

1. Numbers: Investigating if 111 and 100.005 lead to special patterns.
2. Square relations: Checking if $A \times B + 1$ forms a perfect square.

Activité 15:

Explores comparisons of real numbers:

1. Comparing: $a^3 \geq a^2 \geq a$.
2. Concrete relations: Understanding relations between real numbers through visual representation.

Do you have a specific question about one of these activities, or would you like me to work through one of the problems?

Here are 5 related questions to help with further understanding:

1. Can you identify any patterns in the sums listed in Activité 13?
2. How would you approach finding if a product plus one is a perfect square, as in Activité 14?
3. In Activité 12, can you form a conjecture based on the sums given?
4. How do you compare real numbers like $a^3$ and $a^2$ as shown in Activité 15?
5. What is the significance of the large numbers in Activité 13?

Tip: When solving complex sums or conjectures, breaking down the problem into smaller, simpler parts often helps reveal patterns or insights.