Đáp án + Giải thích các bước giải:
f, `-2/3 . (-9)/12`
`= 2/3 . 9/12`
` = 1/2`
h, `4 . (-1/3)^3 - 2 . (-1/2)^2 + 3 . 1/2 + 1`
` = 4 . (-1)/27 - 2 . 1/4 + 3/2 + 1`
` = -4/27 - 1/2 + 3/2 + 1`
` = -4/27 + 1 + 1`
` = -4/27 + 2`
` = -4/27 + 54/27`
` = 50/27`
k, `(4 - 5/12) : 2 + 5/24`
` = (48/12 - 5/12) : 2 + 5/24`
` = 43/12 : 2 + 5/24`
` = 43/24 + 5/24`
` = 48/24 = 2`
o, `0,25 . 1 3/5 . (5/4)^2 : (-4)/7`
` = 1/4 . 8/5 . 25/16 . (-7)/4`
` = 2/5 . 25/16 . (-7)/4`
` = 5/8 . (-7)/4`
` = -35/32`
p, `1/15 + 1/35 + 1/63 + 1/99 + 1/143 + 1/195`
` = 1/(3.5) + 1/(5.7) + 1/(7.9) + 1/(9.11) + 1/(11.13) + 1/(13.15)`
` = 1/2 . ( 2/(3.5) + 2/(5.7) + 2/(7.9) + 2/(9.11) + 2/(11.13) + 2/(13.15) )`
` = 1/2 . ( 1/3 - 1/5 + 1/5 - 1/7 + 1/7 - 1/9 + 1/9 - 1/11 + 1/11 - 1/13 + 1/13 - 1/15)`
` = 1/2 . (1/3 - 1/15)`
` = 1/2 . ( 5/15 - 1/15)`
` = 1/2 . 4/15`
` = 2/15`
q, `4/9 : (-1/7) +6 5/9 : (-1/7)`
` = 4/9 . (-7) + 6 5/9 . (-7)`
` = (-7) . ( 4/9 + 6 5/9)`
` = (-7) . 7`
` = -49`