Составьте все возможные суммы и разности чисел 5 / 6 8 / 9 11 / 12 Найдите значение

1)) 5/6 + 8/9 = (5•3) / (6•3) + (8•2) / (9•2) = 15/18 + 16/18 = 31/18 = 1 13/18;

2)) 5/6 + 11/12 = (5•6) / (6•6) + (11•3) / (12•3) = 30/36 + 33/36 = 63/36 = 1 27/36 = 1 9/12 = 1 3/4;

(сократили 27/36 на 3; и снова 9/12 на 3; можно сразу 27/36 на 9 сократить) ;

Или лучше так решить, меньше знаменатель 5/6+11/12 = (5•2) / (6•2) + 11/12 = 10/12 + 11/12 = 21/12 = 1 9/12 = 1 3/4; (9/12 на 3 сократили)

3)) 8/9 + 11/12 = (8•4) / (9•4) + (11•3) / (12•3) = 32/36+33/36 = 65/36 = 1 29/36;

В сумме 8/9 + 5/6 и 11/12 + 5/6 и 11/12 + 8/9 будет то же самое в ответах;

4)) 8/9+5/6 = (8•2) / (9•2) + (5•3) / (6•3) = 16/18 + 15/18 = 31/18 = 1 13/18;

5)) 11/12 + 5/6 = 11/12 + (5•2) / (6•2) = 11/12 + 10/12 = 21/12 = 1 9/12 = 1 3/4;

6)) 11/12+8/9 = (11•3) / (12•3) + (8•4) / (9•4) = 33/36 + 32/36 = 65/36 = 1 29/36

Разность; 1)) 5/6 - 8/9 = (5•6) / (6•6) - (8•4) / (9•4) = 30/36 - 32/36 = - 2/36 = - 1/18;

(сократили 2/36 на 2) ;

2)) 8/9 - 5/6 = (8•4) / (9•4) - (5•6) / (6•6) = 32/36 - 30/36 = 2/36 = 1/18;

3)) 5/6 - 11/12 = (5•2) / (6•2) - 11/12 = 10/12 - 11/12 = - 1/12;

4)) 11/12 - 5/6 = 11/12 - (2•5) / (6•2) = 11/12 - 10/12 = 1/12;

5)) 8/9 - 11/12 = (8•4) / (9•4) - (11•3) / (12•3) = 32/36 - 33/36 = - 1/36;

6)) 11/12 - 8/9 = (11•3) / (12•3) - (8•4) / (9•4) = 33/36 - 32/36 = 1/36;