Write the following proposition in the form of "if ~, then ~", point out the proposition and conclusion, and judge the truth of the proposition (1) The complement of an equal angle is equal (2) The internal stagger angles are equal and the two lines are parallel (3) Rational numbers must be natural numbers (4) Two straight lines are parallel and have the same angle (5) Two equal angles must be opposite vertex angles

Write the following proposition in the form of "if ~, then ~", point out the proposition and conclusion, and judge the truth of the proposition (1) The complement of an equal angle is equal (2) The internal stagger angles are equal and the two lines are parallel (3) Rational numbers must be natural numbers (4) Two straight lines are parallel and have the same angle (5) Two equal angles must be opposite vertex angles

(1) If two angles are equal, then their complements are equal
(2) If the internal angles are equal, the two lines are parallel
(3) If a number is rational, then it must be natural
(4) If two lines are parallel, then the angles are equal
(5) If two angles are equal, they must be opposite vertex angles
1. 2, 4 to 3, 5 wrong

Point out the propositions and conclusions of the following true propositions, and judge whether they are true propositions or false propositions. If they are false propositions, give a counterexample
(1) When the sum of two angles is equal to a flat angle, the two angles complement each other;
(2) The internal stagger angles are equal;
(3) Two parallel lines are cut by the third straight line with equal internal stagger angle;

(1) Suppose: if the sum of two angles is equal to a flat angle. Conclusion: then the two angles complement each other
(2) Suppose: if two angles are internal stagger angles. Conclusion: then the two angles are equal. As long as two nonparallel straight lines are drawn, the internal stagger angles formed by the third straight line are not equal
(3) Suppose: if two straight lines are parallel. Conclusion: then the two straight lines are cut by the third straight line to form the same internal angle. True proposition

There are also true propositions and false propositions,

A proposition consists of a proposition and a conclusion. A proposition is a known matter, and a conclusion is a matter derived from a known matter. A proposition can often be written in the form of "if. Then." if it is followed by a proposition, then it is followed by a conclusion

What is the definition of proposition in mathematics

Generally, in mathematics, we call statements which can be judged true or false by language, symbol or formula as propositions