27+12
cho 12-x / 27-y =12 /27 . so sanh x/y va 12/27
(-12)+(12)+27-12-|-27|
(-12)+12+27-12-|-27|
= 0 + 27 - 12 - 27
= 27 - 27 - 12
= 0 - 12
= -12
27.(15-12)-15.(27-12)
=27.15-27.12-15.27+15.12
=-27.12+15.12
=12.(-27+15)
=12.(-12)
=-144
Cách 2
=27.3-15.15
=81-225
=-144
-4/27 - 7/12 + -23/27 + 17/12
- \(\dfrac{4}{27}\) - \(\dfrac{7}{12}\) - \(\dfrac{23}{27}\) + \(\dfrac{17}{12}\)
= - (\(\dfrac{4}{27}\) + \(\dfrac{23}{27}\)) + (\(\dfrac{17}{12}\) - \(\dfrac{7}{12}\))
= - \(\dfrac{27}{27}\) + \(\dfrac{10}{12}\)
= -1 + \(\dfrac{5}{6}\)
= - \(\dfrac{6}{6}\) + \(\dfrac{5}{6}\)
= - \(\dfrac{1}{6}\)
27 x (15 – 12) – 15 x ( 27 – 12 )
[(-27+27]+[27.(-1)]+[(1011.(-12)
=0+27+(+12132)
=27+(-12132)
=12159
So sánh :( -12 ) . ( -45 ) : ( -27 ) với |-1|
Làm :
Ta có : ( -12 ) . ( -45 ) : ( -27 ) = 540 : ( -27 ) = -20
Vì -20 < 1 nên ( -12 ) . ( -45 ) : ( -27 ) < |-1|
Cách làm này đúng không ạ?
27.(15-12)-15.(27-12)
Cảm ơn trước
27.(15-12)-15.(27-12)
= 27 . 15 - 27 . 12 - 15 . 27 - 15 . 12
= ( 27 . 15 - 15 . 27 ) - 12. ( 27 - 12 )
= 0 - 12 . 5
= 0 - 60
= -60
27.(15-12)-15.(27-12)
= 27.15- 27.12 - 15.27 - 15.12
= 27 ( 15-15) - 12( 27-15)
= 27.0 - 12.12
= 0 - 144
= -144
đề là tính à bn
Phân số \(\dfrac{4}{9}\)bằng phân số nào dưới đây:
a. \(\dfrac{8}{27}\)
b. \(\dfrac{16}{27}\)
c. \(\dfrac{12}{18}\)
d. \(\dfrac{12}{27}\)
g) (15 + 37) + (52 – 37 – 17) h) (38 – 42 +14) - (38 – 42 - 15) i) (27 + 65 ) + (346 - 27- 65) k) - (27 + 65) - (346 – 27 - 65) l) (42 – 69 + 17) - (42 + 17) m) 24. (16 - 5) – 16. (24 – 5 ) n) (-12). 47 – 12 . 52 + (-12) p) 51 . (69 - 25) – 69. (51 - 25) |
g) (15 + 37) + (52 – 37 – 17) = 15 + 37 + 52 – 37 – 17 = 15 + 52 – 17 = 50 h) (38 – 42 +14) - (38 – 42 - 15) = 38 – 42 +14 - 38 + 42 + 15 = 14 + 15 = 29 i) (27 + 65 ) + (346 - 27- 65) = 27 + 65 + 346 - 27- 65 = 346 k) - (27 + 65) - (346 – 27 - 65) = -27 - 65 - 346 + 27 + 65 = -346 l) (42 – 69 + 17) - (42 + 17) = 42 – 69 + 17 - 42 - 17 = – 69 m) 24. (16 - 5) – 16. (24 – 5 ) = 24. 16 - 24 . 5 - 16 . 24 + 16. 5 = - 24 . 5 + 16. 5 = -8 . 5 = -40 n) (-12). 47 – 12 . 52 + (-12) = -12 (47 - 52 + 1) = -12 . (-4) = 48 p) 51 . (69 - 25) – 69. (51 - 25) = 51 . 69 - 51 . 25 – 69. 51 + 69. 25 = - 51 . 25 + 69. 25 = (- 51+ 69).25 = 450 |