№26
Вопрос
Номер 2.
Вычислите разность.
а) 3 7/10 – 1 4/15 ; НОК (10, 15) = 30, 3 7/10 (3 – 1 4/15 (2 = 3 21/30 – 1 8/30 = (3 – 1) + ( 21/30 – 8/30 ) = 2 + 21 – 8/30 = 2 + 13/30 = 2 13/30 . б) 5 1/12 - 2 7/15 ; НОК (12, 15) = 60, 5 1/12 (5 – 2 7/15 (4 = 5 5/60 – 2 28/60 = (4 + 1 + 5/60 ) – 2 28/60 = (4 + 60/60 + 5/60 ) – 2 28/60 = 4 65/60 – 2 28/60 = 2 65 – 28/60 =2+ 37/60 = 2 37/60 . в) 6 9/35 – 5 13/20 ; НОК (35, 20) = 140, 6 9/35 (4 – 5 13/20 (7 = 6 36/140 – 5 91/140 = (5 + 1 + 36/140 ) – 5 91/140 = (5 + 140/140 + 36/140 ) – 5 91/140 = 5 176/140 – 5 91/140 = 176 – 91/140 = 85/140 = 17/28 . г) 4 7/30 - 3 5/42 ; НОК (30, 42) = 210, 4 7/30 (7 – 3 5/42 (5 = 4 49/210 – 3 25/210 = (4 – 3) + ( 49/210 – 25/210 ) = 1 + 49 – 25/210 = 1 + 24/210 = 1 24/210 = 1 4/35 .
7/10
4/15
7/10
4/15
21/30
8/30
21/30
8/30
21 – 8/30
13/30
1/12
7/15
1/12
7/15
5/60
28/60
5/60
28/60
60/60
5/60
28/60
65/60
28/60
65 – 28/60
37/60
9/35
13/20
9/35
13/20
36/140
91/140
36/140
91/140
140/140
36/140
91/140
176/140
91/140
176 – 91/140
85/140
17/28
7/30
5/42
7/30
5/42
49/210
25/210
49/210
25/210
49 – 25/210
24/210
4/35
Вопрос
Номер 3.
Найдите разность, представив смешанные числа в виде неправильных дробей.
а) 4 5/6 – 2 3/8 = 29/6 (4 – 19/8 (3 = 116 – 57/24 = 59/24 = 2 11/24 ; б) 5 1/9 –3 5/12 = 49/6 (4 – 41/12 (3 = 184 – 123/36 = 61/36 = 1 25/36 .
5/6
3/8
29/6
19/8
116 – 57/24
59/24
11/24
1/9
5/12
49/6
41/12
184 – 123/36
61/36
25/36
