a , -1,8+(1+4/5)
b , 11/21+5/6÷6/8-5/6.6/7
c , -3/8.16.8/17-0,375.79/17
d , (-1/2)÷1/3/8-25% [-6/2/11]
a , -1,8+(1+4/5) b , 11/21+5/6÷6/8-5/6.6/7 c , -3/8.16.8/17-0,375.79/17 d , (-1/2)÷1/3/8-25% [-6/2/11]
By Harper
By Harper
a , -1,8+(1+4/5)
b , 11/21+5/6÷6/8-5/6.6/7
c , -3/8.16.8/17-0,375.79/17
d , (-1/2)÷1/3/8-25% [-6/2/11]
a , -1,8+(1+4/5)
= -9/5 + 9/5 =0
b , 11/21+5/6÷6/8-5/6.6/7
=11/21+5/6 : 6/8-5/6 : 7/6
=11/21 + 5/6 : (6/8 – 7/6)
=11/21 + 5/6 : (-5/12)
=11/21 + (-2)
= -31/21
c , -3/8.16.8/17-0,375.79/17
=-3/8 . 16 . 8/17 – 3/8 . 79/17
=-3/8 . 128/17 – 3/8 . 79/17
=3/8 . (-128/17) – 3/8 . 79/17
=3/8 . (-128/17 – 79/17)
=3/8 . (-207/17)
=-621/136
d , (-1/2)÷1/3/8-25% [-6/2/11]
=-1/2 : 11/8 – 1/4 . (-68/11)
=-4/11 – (-17/11)
=13/11
Đáp án:
`a)`
` -1,8 + (1+ \frac{4}{5}) = -1,8 + ( 1 + 0,8)`
` = -1,8 + 1,8`
` = 0`
`b)`
`\frac{11}{21} + \frac{5}{6} : \frac{6}{8} – \frac{5}{6}. \frac{6}{7}`
` = \frac{11}{21} + \frac{10}{9} – \frac{5}{7}`
` = \frac{103}{63} – \frac{5}{7}`
` = \frac{58}{63}`
`c)`
`\frac{-3}{8}.16.\frac{8}{17} – 0,375. \frac{79}{17}`
` = \frac{-3}{18}. \frac{128}{17} + \frac{-3}{8}. \frac{79}{17}`
` = \frac{-3}{18}. (\frac{128}{17} + \frac{-273}{136})`
` = \frac{-3}{18}. \frac{787}{136}`
` =\frac{-787}{816}`
`d)`
` \frac{-1}{2}: 1\frac{3}{8} – 25%. (-6\frac{2}{11})`
` = \frac{-1}{2} : \frac{11}{8} – \frac{1}{4}. \frac{-68}{11}`
` = \frac{-11}{16} – \frac{-17}{11}`
` = \frac{17}{16}`