Вычислите:5/18+2/9; 9/16+1/2; 1/9+2/3; 1целая1/2+3/16; 1целая5/16+2целых3/8; 17/18-5/6; 1целая3/10-4/5; 2целых8/21-5/7; 3целых2/3-7/9; 1целая5/6-11/12; 2целых1/4+1целая5/12;

1) 5/18 + 2/9 = 5/18 + 2 * 2/9 * 2 = 5/18 + 4/18 = 9/18 = 1/2;

2) 9/16 + 1/2 = 9/16 + 1 * 8/2 * 8 = 9/16 + 8/16 = 17/16 = 1 1/16;

3) 1/9 + 2/3 = 1/9 + 2 * 3/3 * 3 = 1/9 + 6/9 = 7/9;

4) 1 1/2 + 3/16 = 1 * 2 + 1/2 + 3/16 = 3/2 + 3/16 = 3 * 8/2 * 8 + 3/16 = 24/16 + 3/16 = 27/16 = 1 11/16;

5) 1 5/16 + 2 3/8 = 1 * 16 + 5/16 + 2 * 8 + 3/8 = 21/16 + 19/8 = 21/16 + 19 * 2/8 * 2 = 21/16 + 38/16 = 59/16 = 3 11/16;

6) 17/18 - 5/6 = 17/18 - 5 * 3/6 * 3 = 17/18 - 15/18 = 2/18 = 1/9;

7) 1 3/10 - 4/5 = 1 * 10 + 3/10 - 4/5 = 13/10 - 4/5 = 13/10 - 4 * 2/5 * 2 = 13/10 - 8/10 = 5/10 = 1/2;

8) 2 8/21 - 5/7 = 2 * 21 + 8/21 - 5/7 = 50/21 - 5/7 = 50/21 - 5 * 3/7 * 3 = 50/21 - 15/21 = 35/21 = 5 * 7/3 * 7 = 5/3 = 1 2/3;

9) 3 2/3 - 7/9 = 3 * 3 + 2/3 - 7/9 = 11/3 - 7/9 = 11 * 3/3 * 3 - 7/9 = 33/9 - 7/9 = 26/9 = 2 8/9;

10) 1 5/6 - 11/12 = 1 * 6 + 5/6 - 11/12 = 11/6 - 11/12 = 11 * 2/6 * 2 - 11/12 = 22/12 - 11/12 = 11/12;

11) 2 1/4 + 1 5/12 = 2 * 4 + 1/4 + 1 * 12 + 5/12 = 9/4 + 17/12 = 9 * 3/4 * 3 + 17/12 = 27/12 + 17/12 = 44/12 = 4 * 11/4 * 3 = 11/3 = 3 2/3;

12) 2 11/15 - 1 2/5 = 2 * 15 + 11/15 - 1 * 5 + 2/5 = 41/15 - 7/5 = 41/15 - 7 * 3/5 * 3 = 41/15 - 21/15 = 20/15 = 4 * 5/3 * 5 = 4/3 = 1 1/3.