Question

Сложить дроби 7/40 11/70 13/30

Answer 1

$\frac{7}{40} + \frac{11}{70} + \frac{13}{30} = \\ \\ = \frac{7*21}{840} + \frac{11*12}{840} + \frac{13*28}{840} = \\ \\ = \frac{147+132+364}{840} = \frac{643}{840}$