Riddles with matrices

Puzzles, riddles, brain teasers, conundrums, logic questions in pictures. Here all tasks are presented in the form of various matrices. Most often these are rectangular matrices that have external rows and columns. In these logic puzzles, brain teasers and conundrums, the columns and rows affect the contents of the matrices. To check your answer, click on the «Answer» button located below the task. After this, the correct answer and explanations will appear. Below you can select other questions on this topic. Typically each topic has 20 questions or more. At the same time, the complexity of logical problems gradually increases. First there will be easy questions, then medium, then difficult. Try to complete tasks as quickly as possible.
Question - 1
In this riddle you need to determine what number each geometric object corresponds to. On the right and above are the sums of the values ​​of all objects in the vertical and horizontal rows. What number should be placed instead of the question mark?
Correct answer = 7.
The method for calculating the values ​​of geometric objects is shown below. Although this is not the only option for solving this problem. Since three circles are equal to the number 3, then one circle is equal to the number 1. Now you can substitute the value of the circle in the first line. It becomes obvious that the yellow rectangle is equal to the number 2. If the value of the rectangle is substituted in the left column, it will become obvious that the blue star is equal to the number 4. We substitute all the values ​​of the geometric objects in the bottom row. We get the answer = 7.
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