Half of 4 is 2. 7. AND When two statements are connected by the word and , it does not matter which statement is first. For example, the composite statement There are 25.4 millimetres in one inch, and twelve inches make one foot has the same meaning as Twelve inches make one foot, and there are 25.4 millimetres in one inch . Both of these composite statements have the same meaning. As a result of this law we may omit the brackets and write p and q and r.
Birds are animals .
The freezing point of water is zero degrees Celsius . When any statement is connected to its negation by the word and the resulting composite statement is false. For example, the composite statement They have a motorcar, and they do not have a motor car is false. This is called the law of contradiction . The time is after twelve o'clock, and the time is before twelve o'clock.