Ответы
1 вариант
1.
а) 4/11 + 3/11 = 7/11
б) 1/5 + 3 = 3 1/5
в) 1 2/5 + 1 1/2 = 1 4/10 + 1 5/10 = 2 9/10
2.
а) 7/12 - 1/8 = 14/24 - 3/24 = 11/24
б) 4 - 2 5/13 = 3 13/13 - 2 5/13 = 1 8/13
в) 3 3/18 - 1 5/6 = 57/18 - 11/6 = 57/18 - 33/18 = 24/18 = 1 6/8 = 1 3/4
3.
а) 3/4 × 5/9 = 1/4 × 5/3 = 5/12
б) 6 × 5/36 = 6/1 × 5/36 = 1/1 × 5/6 = 5/6
в) 3 2/3 × 1 4/5 = 3 8/15
4.
а) 6/25 : 9/5 = 6/25 × 5/9 = 2/5 × 1/3 = 2/15
б) 6 2/3 : 1 1/8 = 20/3 : 9/8 = 20/3 × 8/9 = 160/27 = 5 25/27
в) 15 : 5/14 = 15/1 : 5/14 = 15/1 × 14/5 = 3/1 × 14/1 = 42/1 = 42
5.
5/9х = 7/18 - 1/9
5/9х = 7/18 - 2/18
5/9х = 5/18
х = 5/18 : 5/9
х = 5/18 × 9/5
х = 1/2 ×1/1
х = 1/2
2 вариант
1.
а) 4/19 + 3/19 = 7/19
б) 1/7 + 4 = 4 1/7
в) 1 3\4 + 3 5/6 = 1 9/12 + 3 10/12 = 4 19/12 = 5 7/12
2.
а) 7/16 - 1/4 = 7/16 - 4/16 = 3/16
б) 3 - 2 6/11 = 2 11/11 - 2 6/11 = 5/11
в) 4 1/6 - 2 5/16 = 25/6 - 37/16 = 200/48 - 111/48 = 89/48 = 1 41/48
3.
а) 3/8 × 2/21 = 1/4 × 1/7 = 1/28
б) 6 × 4/9 = 6/1 × 4/9 = 2/1 × 4/3 = 8/3 = 2 2/3
в) 3 1/3 × 1 1/5 = 3 1/15
4.
а) 4/15 : 16/5 = 4/15 × 5/16 = 1/3 × 1/4 = 1/12
б) 3 2/9 : 2 1/3 = 29/9 : 7/3 = 29/9 × 3/7 = 29/3 × 1/7 = 29/21 = 1 8/21
в) 18 : 9/11 = 18/1 : 9/11 = 18/1 × 11/9 = 2/1 × 11/1 = 22/1 = 22
5.
5/6х = 1/6 + 2/3
5/6х = 1/6 + 4/6
5/6х = 4/6
х = 4/6 : 5/6
х = 4/6 × 6/5
х = 4/1 × 1/5
х = 4/5