( 1 2/7 * 5 4/9 - 3 2/3 ) : 2,5
1) 1 2/7 • 5 4/9 = 9/7 • 49/9 = 49/7 = 7 2) 7 - 3 2/3 = 6 3/3 - 3 2/3 = 3 1/3 3) 3 1/3 : 2,5 = 10/3 : 5/2 = 4/3 = 1 1/3 Ответ 1 1/3