Математика 5 класс контрольные работы Крайнева ответы – страница 35

а) 90/630 = ̶ ̶9̶ ∙ ̶ ̶1̶0̶ /7 ∙ ̶9̶ ∙ ̶1̶0̶ = 1/7 б) 8/14 = ̶2̶ ∙ 4/ ̶2̶ ∙ 7 = 4/7 в) 3/27 = ̶ ̶3̶ ̶/9 ∙ ̶ ̶3̶ ̶ = 1/9 г) 34 ∙ 12 /3 ∙ 17 = 2 ∙ ̶1̶7̶ ∙ ̶3̶ ∙ 4/3 ∙ ̶1̶7̶ = 8     1/9 < 1/7 < 4/7 < 8
Ответ: 1/9; 1/7; 4/7; 8.

а) 1/5 + 4/11 = 11/55 + 20/55 = 31/55 б) 3/7 + 5/14 = 6/14 + 5/14 = 11/14 в) 8/9 – 7/12 = 32/36 – 21/36 = 11/36 г) 11/50 – 3/25 + 1/20 = 22/100 – 22/100 + 5/100 = 15/100 = 3/20

а) 7/9 и n/18     7 ∙ 2/9 ∙ 2 = 14/18      n = 14 б) 1/7 и 5/c     1/7 = 1 ∙ 5/7 ∙ 5 = 1 ∙ 5/7 ∙ 5 = 5/7 ∙ 35       c = 35

11/12 – y = 13/24 y = 11/12 – 13/24 y = 22/24 – 13/24 y = 9/24 y = 3/8

1) 513/18 – 37/36 = 526/36 – 37/36 = 219/36 2) 45/6 – 219/36 = 430/36 – 219/36 = 211/36
Ответ: 211/39

а) 90/450 = ̶ ̶9̶ ∙ ̶1̶0̶ /5 ∙ ̶ ̶9̶ ∙ ̶ ̶1̶0̶ = 1/5 б) 6/16 = ̶2̶ ∙ 3/ ̶2̶ ∙ 8 = 3/8 в) 8/88 = ̶8̶ /11 ∙ ̶ ̶8̶ = 1/11 г) 36 ∙ 14/7 ∙ 12 = 3 ∙ ̶ ̶1̶2̶ ∙ 7 ∙ 2/7 ∙ ̶1̶2̶ = 6 1/11 < 1/5 < 3/8 < 6
Ответ: 6; 3/8; 1/5; 1/11

а) 1/6 + 3/7 = 7/42 + 18/42 = 25/42 б) 3/8 + 7/16 = 6/16 + 7/16 = 13/16 в) 7/15 – 3/20 = 28/60 – 9/60 = 19/60 г) 1/8 + 5/6 – 7/12 = 3/24 + 20/24 – 14/24 = 9/24 = 3/8

а) 5/6 и k/30      5/6 = (5 ∙ 5)/(6 ∙ 5) = 25/30       k = 25
б) 1/13 и 3/t      1/13 = (1 ∙ 3)/(13 ∙ 3) = 3/39       t = 39

7/11 – х = 5/33 х = 7/11 – 5/33 х = 21/33 – 5/33 х = 16/33

1) 817/20 – 47/10 = 817/20 – 414/20 = 43/20 2) 12/5 + 43/20 = 18/20 + 43/20 = 511/20
Ответ: 511/20.