② A rectangle has (2) symmetry axes.

③ A circle is a (symmetrical) figure with (countless) symmetry axes.

(4) The first digit to the right of the decimal point is the (tenth) digit, and its calculation unit is (tenth).

⑤ The calculation unit of 3.05 is (one percent), and it has such a unit as (305).

⑥ The sum of a and b is 15.4. If the decimal point of the known number A is shifted one place to the left, the number B is (14) and the number B is (1.4).

⑦ After the decimal point of a number is shifted to the right by one place, the number obtained is 3.6 larger than the original number, so the original number is (0.4).

A figure composed of two lines drawn from a point is called an angle. This point is called the vertex of an angle. These two lines are called edges and corners. An angle is usually represented by a symbol ("∞").