10. (5 points) There are the following statements:
(1) A obtuse angle minus a right angle will definitely result in an acute angle.
(2) An obtuse angle minus an acute angle cannot still be an obtuse angle.
(3) Among the three interior angles of a triangle, there is at most one obtuse angle.
(4) Among the three interior angles of a triangle, there are at least two acute angles.
(5) The three interior angles of a triangle can all be acute.
(6) A right triangle can have an obtuse angle.
(7) A $25^{\circ}$ angle will become $250^{\circ}$ when viewed through a 10x magnifying glass.

Among these, the number of correct statements is $\qquad$.
【Analysis】(1) An obtuse angle is an angle greater than 90 degrees and less than 180 degrees, so subtracting a right angle from an obtuse angle will result in an acute angle;
(2) An obtuse angle is an angle greater than 90 degrees and less than 180 degrees, and an acute angle is an angle less than 90 degrees, so subtracting an acute angle from an obtuse angle may still result in an obtuse angle;
(3) The sum of the interior angles of a triangle is 180 degrees, and an obtuse angle is an angle greater than 90 degrees and less than 180 degrees, so a triangle can have at most one obtuse angle;
(4) The sum of the interior angles of a triangle is 180 degrees, an obtuse angle is an angle greater than 90 degrees and less than 180 degrees, and a right angle is 90 degrees, so a triangle must have at least two acute angles;
(5) Because the sum of the interior angles of a triangle is 180 degrees, and an acute angle is an angle less than 90 degrees, the three interior angles of a triangle can all be acute angles;
(6) In a right triangle, the sum of the other two acute angles is also 90 degrees, so it is impossible to have another obtuse angle;
(7) The degree of an angle is only related to the size of the opening between its two sides.

【Solution】(1) Since an obtuse angle is an angle greater than 90 degrees and less than 180 degrees, subtracting a right angle from an obtuse angle will result in an acute angle, so this statement is correct;
(2) Since an obtuse angle is an angle greater than 90 degrees and less than 180 degrees, and an acute angle is an angle less than 90 degrees, subtracting an acute angle from an obtuse angle may still result in an obtuse angle, so this statement is incorrect;
(3) Since the sum of the interior angles of a triangle is 180 degrees, and an obtuse angle is an angle greater than 90 degrees and less than 180 degrees, if a triangle has more than one obtuse angle, it would not conform to the triangle angle sum theorem, so this statement is correct;
(4) Since the sum of the interior angles of a triangle is 180 degrees, an obtuse angle is an angle greater than 90 degrees and less than 180 degrees, and a right angle is 90 degrees, a triangle must have at least two acute angles, so this statement is correct;
(5) Since the sum of the interior angles of a triangle is 180 degrees, and an acute angle is an angle less than 90 degrees, the three interior angles of a triangle can all be acute angles, so this statement is correct;
(6) In a right triangle, the sum of the other two acute angles is also 90 degrees, so it is impossible to have another obtuse angle, so this statement is incorrect;
(7) Since the degree of an angle is only related to the size of the opening between its two sides, and not to how many times it is magnified, so this statement is incorrect; hence the answer is: 4.