Tính nhanh:56*2+28*5+28
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Ta có:56x2+28x5 +28
=28x2x2+28x5+28
=28x4+28x5+28
=28x(4+5+1)
=28x10=280
56 x 2 + 28 x 5 + 28
= 28 x 2 x 2 + 28 x 5 + 28 x 1
= 28 x 4 + 28 x 5 + 28 x 1
= 28 x ( 4 + 5 + 1 )
= 28 x 10
= 280
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\(\dfrac{-3}{5}+\dfrac{28}{5}.\left(\dfrac{43}{56}+\dfrac{5}{24}-\dfrac{21}{63}\right)\)
= \(\dfrac{-3}{5}+\dfrac{28}{5}.\dfrac{9}{14}\)
= \(\dfrac{-3}{5}+\dfrac{28.9}{5.14}\)
= \(\dfrac{-3}{5}+\dfrac{18}{5}\)
= \(\dfrac{\left(-3\right)+18}{5}\)
= \(\dfrac{15}{5}=3\)
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234 + 28 - ( -234 ) + ( -108 ) + 120=234+28+234-108+120
=234+(108+120)-28=234+(228-28)
=234+200=434
625 - ( 127 - 56 ) + ( 144 - 625 )=625-127+56+144-625
=127+(625-625)+(144+56)=127+0+200
=127+200=327
Cho mk xin lỗi bài mk sai nha bn
Lời giải:
$234+28-(-234)+(-108)+120=234+28+234-108+120$
$=234.2-(108-28)+120$
$=468-80+120=468+40=508$
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$625-(127-56)+(144-625)=625-127+56+144-625$
$=(625-625)+(144+56)-127$
$=0+200-127=73$
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28 x 34 - 17 x 56 + 1000
= 28 x 34 - 17 x 2 x 28 + 1000
= 28 x 34 - 34 x 28 + 1000
= 28 x (34 - 34) + 1000
= 28 x 0 + 1000
= 0 + 1000 = 1000
280 nho like cho minh nhe