Вычислите, применяя перемистительное и сочитательное характеристики умножения: 1)1целая2/7+2целых5/6+3целых5/7+1целая1/6 2)4/9+1целая2/3+2целых5/9+1/3 3)2целых1/5+3/8+1целая4/5+5/8 4)1целая3/10+1/4+2целых7/10+3/4

1) 1 2/7 + 2 5/6 + 3 5/7 + 1 1/6 = (1 * 7 + 2)/7 + (2 * 6 + 5)/6 + (3 * 7 + 5)/7 + (1 * 6 + 1)/6 = 9/7 + 17/6 + 26/7 + 7/6 = (9 + 26)/7 + (17 + 7)/6 = 35/7 + 24/6 = 5 + 4 = 9.

2) 4/9 + 1 2/3 + 2 5/9 + 1/3 = 4/9 + (1 * 3 + 2)/3 + (2 * 9 + 5)/9 + 1/3 = 4/9 + 5/3 + 23/9 + 1/3 = (4 + 23)/9 + (5 + 1)/3 = 27/9 + 6/3 = 3 + 2 = 5.

3) 2 1/5 + 3/8 + 1 4/5 + 5/8 = (2 * 5 + 1)/5 + 3/8 + (1 * 5 + 4)/5 + 5/8 = 11/5 + 3/8 + 9/5 + 5/8 = (11 + 9)/5 + (3 + 5)/8 = 20/5 + 8/8 = 4 + 1 = 5.

4) 1 3/10 + 1/4 + 2 7/10 + 3/4 = (1 * 10 + 3)/10 + 1/4 + (2 * 10 + 7)/10 + 3/4 = 13/10 + 1/4 + 27/10 + 3/4 = (13 + 27)/10 + (1 + 3)/4 = 40/10 + 4/4 = 4 + 1 = 5.