Multiplying Rational Numbers How can a number be a rational one?! Any number could be a rational if it represents a ratio between two integers A and B where B is the denominator which doesn't equal zero. like for example, 3 over 4, 17 over 45 and 101 over 585 .. This term was first to be released by the Italian Mathematician: Giuseppe Peano. If we are multiplying 2 by 3, the result is concretely 6 but, if I won't to maximize this 6 to make it equal to 6 over 7, you would try to multiply (2*3) by 1 over 7. We can't distribute this as 2/7 multiplied by 3/7, but we can multiply the numbers easily and normally to get 6 and then we divide by 7. The note here is that: in case of having a same denominator, we fix this denominator and add the numerators easily. Rule 1: Any integer N is a rational number too, equivalent to N/1 . Rule 2: If two rational numbers a/b and c/d were multiplied by each other, The result is (a . c)/(b . d). Rule 3: If a.c and b.d have a common factor, we simplify the whole term. If the numerators and the denominators share no common factor rather than 1, the term is then called Irreducible. Exercises: I) 3/5 * 3/7. II) 5/13 * 11/15. III) 7/15 * 99/21. IV) 6/7 * 5/6. Answers: I) 9/35. II) 11/39. III) 11/5. IV) 5/7.

:ملخص للدرس من اعداد محمد البرديسى