Question

Đã trả lời bởi chuyên gia

Answer 1

ta có:

$1) . \frac{1}{5} : \frac{1}{3} \times \frac{2}{7} : \frac{3}{14} + \frac{9}{4} = \frac{1}{5} \times 3 \times \frac{2}{7} \times \frac{14}{3} + \frac{9}{4} = \frac{2}{5} + \frac{9}{4} = \frac{53}{20} 2) \frac{7}{8} \times \frac{1}{2} + \frac{7}{8} \times \frac{14}{3} - \frac{7}{8} \times 2 = \frac{7}{8} \times (\frac{1}{2} + \frac{14}{3} - 2) = \frac{7}{8} \times \frac{19}{6} = \frac{133}{48} 3) (1998 \times 1999 + 1998 \times 1997) \times (1 + \frac{1}{2} : \frac{3}{2} - \frac{4}{3}) = 1998 \times (1999 + 1997) \times ((1 + \frac{1}{2} \times \frac{2}{3} - \frac{4}{3}) = 1998 \times 3996 \times 0 = 0 4) 18 \times (\frac{191919}{212121} + \frac{88888}{99999}) = 18 \times (\frac{19}{21} + \frac{8}{9}) = 18 \times \frac{113}{63} = \frac{226}{7}$

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Answer 2

ta có:

$1) . \frac{1}{5} : \frac{1}{3} \times \frac{2}{7} : \frac{3}{14} + \frac{9}{4} = \frac{1}{5} \times 3 \times \frac{2}{7} \times \frac{14}{3} + \frac{9}{4} = \frac{2}{5} + \frac{9}{4} = \frac{53}{20} 2) \frac{7}{8} \times \frac{1}{2} + \frac{7}{8} \times \frac{14}{3} - \frac{7}{8} \times 2 = \frac{7}{8} \times (\frac{1}{2} + \frac{14}{3} - 2) = \frac{7}{8} \times \frac{19}{6} = \frac{133}{48} 3) (1998 \times 1999 + 1998 \times 1997) \times (1 + \frac{1}{2} : \frac{3}{2} - \frac{4}{3}) = 1998 \times (1999 + 1997) \times ((1 + \frac{1}{2} \times \frac{2}{3} - \frac{4}{3}) = 1998 \times 3996 \times 0 = 0 4) 18 \times (\frac{191919}{212121} + \frac{88888}{99999}) = 18 \times (\frac{19}{21} + \frac{8}{9}) = 18 \times \frac{113}{63} = \frac{226}{7}$

Answer 3

1,

$\frac{1}{5} : \frac{1}{3} \times \frac{2}{7} : \frac{3}{14} + \frac{9}{4} = \frac{3}{5} \times \frac{2}{7} : \frac{3}{14} + \frac{9}{4} = \frac{6}{35} : \frac{3}{14} + \frac{9}{4} = \frac{4}{5} + \frac{9}{4} = \frac{61}{20}$

2,

$\frac{7}{8} \times \frac{1}{2} + \frac{7}{8} \times \frac{14}{3} - \frac{7}{8} \times 2 = \frac{7}{8} \times (\frac{1}{2} + \frac{14}{3} - 2) = \frac{7}{8} \times \frac{19}{6} = \frac{133}{48}$

3,

$(1998 \times 1999 + 1998 \times 1997) \times (1 + \frac{1}{2} : \frac{3}{2} - \frac{4}{3}) = (1998 \times 1999 + 1998 \times 1997) \times (1 + \frac{1}{3} - \frac{4}{3}) = (1998 \times 1999 + 1998 \times 1997) \times (\frac{4}{3} - \frac{4}{3}) = (1998 \times 1999 + 1998 \times 1997) \times 0 = 0$

4,

$18 \times (\frac{191919}{212121} + \frac{88888}{99999}) = 18 \times (\frac{19 \times 10101}{21 \times 10101} + \frac{8 \times 11111}{9 \times 11111}) = 18 \times (\frac{19}{21} + \frac{8}{9}) = 18 \times \frac{113}{63} = \frac{226}{7}$

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Answer 4

1,

$\frac{1}{5} : \frac{1}{3} \times \frac{2}{7} : \frac{3}{14} + \frac{9}{4} = \frac{3}{5} \times \frac{2}{7} : \frac{3}{14} + \frac{9}{4} = \frac{6}{35} : \frac{3}{14} + \frac{9}{4} = \frac{4}{5} + \frac{9}{4} = \frac{61}{20}$

2,

$\frac{7}{8} \times \frac{1}{2} + \frac{7}{8} \times \frac{14}{3} - \frac{7}{8} \times 2 = \frac{7}{8} \times (\frac{1}{2} + \frac{14}{3} - 2) = \frac{7}{8} \times \frac{19}{6} = \frac{133}{48}$

3,

$(1998 \times 1999 + 1998 \times 1997) \times (1 + \frac{1}{2} : \frac{3}{2} - \frac{4}{3}) = (1998 \times 1999 + 1998 \times 1997) \times (1 + \frac{1}{3} - \frac{4}{3}) = (1998 \times 1999 + 1998 \times 1997) \times (\frac{4}{3} - \frac{4}{3}) = (1998 \times 1999 + 1998 \times 1997) \times 0 = 0$

4,

$18 \times (\frac{191919}{212121} + \frac{88888}{99999}) = 18 \times (\frac{19 \times 10101}{21 \times 10101} + \frac{8 \times 11111}{9 \times 11111}) = 18 \times (\frac{19}{21} + \frac{8}{9}) = 18 \times \frac{113}{63} = \frac{226}{7}$

Answer 5

`1) 1/5 : 1/3 xx 2/7 : 3/14 + 9/4`

`=1/5xx3/1xx2/7xx14/3+9/4`

`=3/5xx2/7xx14/3+9/4`

`=6/35xx14/3+9/4`

`=4/5+9/4`

`=61/20`

``

________________________________________________

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`2) 7/8 xx 1/2 + 7/8 xx 14/3 - 7/8 xx 2`

`=7/8xx(1/2+14/3-2)`

`=7/8xx19/6`

`=133/48`

________________________________________________

`3) (1998 xx 1999 + 1998 xx 1997) xx (1 + 1/2 : 3/2 - 4/3)`

`= (1998 xx 1999 + 1998 xx 1997) xx (1 + 1/2 xx 2/3 - 4/3)`

`= (1998 xx 1999 + 1998 xx 1997) xx (1 + 1/3 - 4/3)`

`= (1998 xx 1999 + 1998 xx 1997) xx (3/3 + 1/3 - 4/3)`

`= (1998 xx 1999 + 1998 xx 1997) xx 0/3`

`= (1998 xx 1999 + 1998 xx 1997) xx 0`

`= 0`

________________________________________________

`18 xx (191919/212121 + 88888/99999)`

`= 18 xx (19/21 + 8/9)`

`= 18 xx (57/63 + 56/63)`

`= 18 xx 113/63`

`= 226/7`

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