Найдите значение выражения а) 1 2/15 - 2 3/10 - 1 1/6= б) 2 5/21 - 4 1/7 + 1 1/14= в) 4 2/35 - 2 5/14 - 1 3/10= г) 1 2/9 + 2 5/6 - 5 1/5=

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милкаshow 05.07.2020 21:16

1)
$1 \frac{2}{15} -2 \frac{3}{10}-1 \frac{1}{6} = 1 \frac{4}{30} -2 \frac{9}{30}-1 \frac{5}{30}= 1 \frac{4}{30} -1 \frac{5}{30}-2 \frac{9}{30}=- \frac{1}{30} -2 \frac{9}{30}=$ $=-2 \frac{10}{30} =-2 \frac{1}{3}$
2)
$2 \frac{5}{21} - 4 \frac{1}{7} + 1 \frac{1}{14} =2 \frac{10}{42} - 4 \frac{6}{42} + 1 \frac{3}{42} =2 \frac{10}{42} + 1 \frac{3}{42} - 4 \frac{6}{42}=3 \frac{13}{42} -4 \frac{6}{42}=$ $= -(4 \frac{6}{42}-3 \frac{13}{42})=-(3 \frac{48}{42}-3 \frac{13}{42})=- \frac{35}{42}=- \frac{5}{6}$
3)
$4 \frac{2}{35} - 2 \frac{5}{14} - 1 \frac{3}{10} =4 \frac{4}{70} - 2 \frac{25}{70} - 1 \frac{21}{70} =3 \frac{74}{70} - 2 \frac{25}{70} - 1 \frac{21}{70} =$ $=1 \frac{49}{70} - 1 \frac{21}{70} = \frac{28}{70}= \frac{4}{10}= \frac{2}{5}$
4)
$1 \frac{2}{9} + 2 \frac{5}{6} - 5 \frac{1}{5} =1 \frac{4}{18}+2 \frac{15}{18}-5 \frac{1}{5}=3 \frac{19}{18}-5 \frac{1}{5}=4 \frac{1}{18}-5 \frac{1}{5}= 4 \frac{5}{90}-5 \frac{18}{90}=$ $=-1 \frac{13}{90}$

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zukhra9087 05.07.2020 21:16

1 2/15 - 2 3/10 - 1 1/6 = - 2 1/3
выражением:
= 1 4/30 - ( 2 9/30 + 1 5/30) =
= 1 4/30 - 3 14/30 =
= - (3 14/30 - 1 4/30) =
= - 2 10/30 = - 2 1/3
по действиям:
1) 1 2/15 - 2 3/10 = 1 4/30 - 2 9/30 = -(2 9/30 - 1 4/30) = - 1 1/6
2) - 1 1/6 - 1 1/6 = - (1 1/6 + 1 1/6) = - 2 2/6 = - 2 1/3

2 5/21 - 4 1/7 + 1 1/14 = - 5/6
выражением:
= 2 10/42 - 4 6/42 + 1 3/42 =
= - (4 6/42 - 3 13/42) =
= - 35/42 = - 5/6
по действиям:
1) 2 5/21 - 4 1/7 = - (4 3/21 - 2 5/21 ) = - 1 19/21
2) - 1 19/21 + 1 1/14 = - 1 38/42 + 1 3/42 = - 35/42 = - 5/6

4 2/35 - 2 5/14 - 1 3/10 = 2/5
выражением:
= 4 4/70 - 2 25/70 - 1 21/70 =
= 4 4/70 - (2 25/70 + 1 21/70) =
= 4 4/70 - 3 46/70 =
= 28/70 = 4/10 = 2/5
по действиям:
1) 4 2/35 - 2 5/14 = 4 4/70 - 2 25/70 = 1 49/70 = 1 7/10
2) 1 7/10 - 1 3/10 = 4/10 = 2/5

1 2/9 + 2 5/6 - 5 1/5 = - 1 13/90
выражением:
= 1 60/270 + 2 225/270 - 5 54/270 =
= 4 15/270 - 5 54/270=
= - (5 54/270 - 4 15/270) =
= - 1 39/270 = - 1 13/90
по действиям:
1) 1 2/9 + 2 5/6 = 1 4/18 + 2 15/18 = 3 + 1 1/18 = 4 1/18
2) 4 1/18 - 5 1/5 = - ( 5 18/90 - 4 5/90) = - 1 13/90

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