tính
a,27.[13-16]-16[13-27]
bài 3 thực hiện phép tính
a\(\dfrac{5}{8}+\dfrac{3}{17}+\dfrac{4}{18}+\dfrac{20}{-17}+\dfrac{-2}{9}+\dfrac{21}{56}\)
b\(\left(\dfrac{9}{16}+\dfrac{8}{-27}\right)+\left(1+\dfrac{7}{16}+\dfrac{-19}{27}\right)\)
c\(\left(\dfrac{13}{5}+\dfrac{7}{16}\right)+\left(\dfrac{-15}{16}+\dfrac{6}{15}\right)\) d \(\left(6-2\dfrac{4}{5}\right).3\dfrac{1}{8}-1\dfrac{3}{5}:\dfrac{1}{4}\)
a) Ta có: \(\dfrac{5}{8}+\dfrac{3}{17}+\dfrac{4}{18}+\dfrac{20}{-17}+\dfrac{-2}{9}+\dfrac{21}{56}\)
\(=\left(\dfrac{3}{17}-\dfrac{20}{17}\right)+\left(\dfrac{2}{9}-\dfrac{2}{9}\right)+\left(\dfrac{5}{8}+\dfrac{3}{8}\right)\)
\(=-1+1=0\)
b) Ta có: \(\left(\dfrac{9}{16}+\dfrac{8}{-27}\right)+\left(1+\dfrac{7}{16}+\dfrac{-19}{27}\right)\)
\(=\left(\dfrac{9}{16}+\dfrac{7}{16}\right)+\left(\dfrac{-8}{27}-\dfrac{19}{27}\right)+1\)
=1-1+1=1
27(13-16)-16(13-27)
\(27\left(13-16\right)-16\left(13-27\right)=27.\left(-3\right)-16.\left(-14\right)=-81+224==143\)
27(13-16)-16(13-27)
27.(13-16)-16.(13-27)
27.(13 - 16) - 16(13 - 27)
= 27 . (-3) - 16.( -14)
= -81 + 224
= 143
\(27\left(13-16\right)-16\left(13-27\right)\\ =27.13-27.16-16.13+16.27\\ =\left(27.16-27.16\right)+13\left(27-16\right)\\ =0+13.11\\ =143\)
27.(13-16)-16.(13-27)
=27.(-3)-16.(-14)
=(-81).(-224)
=18114
~ CHÚC BN HỌC TỐT~
27[13-16]-16.[13-27
27[13-16]-16.[13-27]
=27.(-3)-16.(-14)
=-81-(-224)
=-81+224
=143
27. (13-16) - 16.(13-27)
= 27.13 - 16.27 - 16.13 + 16.27
= 13.(27 - 16)
= 13.11
= 143
27 . ( 13 - 16 ) - 16 . ( 13 - 27 )
=27.13-27.16-16.13+16.27
=27.13-16.13=13.(27-16)
=13.11=143
Từ biểu thức, ta có:
(27.13-27.16)-(16.13-16.27)
= 27.13-27.16-16.13+16.27
=27.13-16.13
=13(27-16)
=13.11
=143
27 . ( 13 - 16 ) - 16 . ( 13 - 27 )
= 27.13 -16.27-16.13 -27.16
= ( 16.27 -27.16) + (27.13 - 16.13)
= 13. ( 27-16)
=13.11
=143
TÍNH NHANH
27.(16-13)-16.(27-13)
27(16-13)-16(27-13)
=27.16-27.13-16.27+16.13
=(27.16-16.27)+(-27.13+16.13)
=0+13(-27+16)
=0+13.-11
=0+-143=-143
Trả lời :
27 .( 16 - 13 ) - 16 . ( 27 - 13 )
= 27 . 16 - 27 . 13 - 16 . 27 + 16 . 13
= ( 27 . 16 - 16 . 27 ) + 16 . 13 - 27 .13
= 0 + 13 . ( 16 - 27 )
= 13 . ( - 11 )
= - 143
- Study well -
27(13-16)-16(13-27)
27(13-16)-16(13-27)
=27.(-3)-16.(-14)
=(-81).(-224)
=18114
=27*(-3)-16*(-14)
=(-81)*(-224)
=18144
DUYỆT NHA