Question 566235
Let *[tex \LARGE \frac{a}{b}] and *[tex \LARGE \frac{c}{d}] be two rational numbers, where a,b,c,d are integers. Then,


*[tex \LARGE \frac{a}{b} + \frac{c}{d} = \frac{ad + bc}{bd}]


Since integers are closed under addition and multiplication, the numerator and denominator will both be integers. Hence, the sum of two rational numbers is a rational number. We can also say that rational numbers are closed under addition.