Lời giải:
a.

$36,5\times 3+36,5\times 5+36,5\times 2=36,5\times (3+5+2)=36,5\times 10=365$

b. Dấu giữa $12,5$ và $0,4$ là gì vậy bạn?

\(a.32,5-3\cdot0,87=32,5-2,61=29,89\)

\(8,5\cdot\left(1\dfrac{1}{2}+\dfrac{4}{4}\right):5=8,5\cdot\left(\dfrac{3}{2}+\dfrac{4}{4}\right):5\\ =8,5\cdot\left(\dfrac{6}{4}+\dfrac{4}{4}\right):5\\ =8,5\cdot\dfrac{10}{4}:5\\ =\dfrac{85}{4}:5\\ =\dfrac{17}{4}\)

\(b.30,96-6,45+14,4:3=30,96-6,45+4,8\\ =29,31\)

\(\dfrac{2}{5}\cdot\left(\dfrac{4}{5}-\dfrac{1}{2}\right)=\dfrac{2}{5}\cdot\left(\dfrac{8}{10}-\dfrac{5}{10}\right)\\ =\dfrac{2}{5}\cdot\dfrac{3}{10}=\dfrac{3}{25}\)

bài 2

\(a.2,5\cdot12,5\cdot8\cdot0,4=\left(2,5\cdot0,4\right)\left(12,5\cdot8\right)\\ =1\cdot100=100\)

b,\(\dfrac{12}{15}\cdot\dfrac{5}{6}\cdot\dfrac{3}{20}\cdot\dfrac{32}{5}=\dfrac{12\cdot5\cdot3\cdot32}{15\cdot6\cdot20\cdot5}\\ =\dfrac{3\cdot4\cdot5\cdot3\cdot4\cdot8}{3\cdot5\cdot2\cdot3\cdot5\cdot4\cdot5}=\dfrac{16}{25}\)

Bài 1: 

a) \(32.5-3\cdot0.87=32.5-2.61=29.89\)

\(8.5\cdot\left(1\dfrac{1}{2}+\dfrac{4}{4}\right):5=8.5\cdot\dfrac{5}{2}:5=\dfrac{17}{2}\cdot\dfrac{5}{2}:5=\dfrac{85}{4}\cdot\dfrac{1}{5}=\dfrac{17}{4}\)

b) \(30.96-6.45+14.4:3=24.51+4.8=29.33\)

\(\dfrac{2}{5}\left(\dfrac{4}{5}-\dfrac{1}{2}\right)=\dfrac{2}{5}\left(\dfrac{8}{10}-\dfrac{5}{10}\right)=\dfrac{2}{5}\cdot\dfrac{3}{10}=\dfrac{6}{50}=\dfrac{3}{25}\)

a) ( - 6,37 x 0,4 ) x 2,5

=-6,37 x (0,4 x 2,5)

=-6,37 x 1

=-6,37

b) ( -0,125 ) x ( -5,3 ) x 8

=(-0,125 x 8) x (-5,3)

=-1 x (-5,3)

=5,3

c) ( -2,5 ) x ( -4 ) x ( -7,9 )

=[(-2,5) x (-4)] x (-7,9)

=10 x (-7,9)

=-79

a)(-6,37x0,4)x2,5=-6,37x(0,4x2,5)=-6,37x1=-6,37

b)(-0,125)x(-5,3)x8=(-0,125x8)x(-5,3)=-1x(-5,3)=5,3

c)(-2,5)x(-4)x(-7,9)=[(-2,5)x(-4)]x(-7,9)=10x(-7,9)=-79

Em ko biết làm

3/5 + 2/7-1/3 trả lời giúp tôi .Nhanh  nhé

a)

\(\left(-6,37.0,4\right)2,5=\left(-6,37\right).\left(\frac{2}{5}.\frac{5}{2}\right)=1.\left(-6,37\right)=-6,37\)

b)

\(\left(-0,125\right)\left(-5,3\right).8=\left[\left(-\frac{1}{8}\right).8\right]\left(-5,3\right)=\left(-1\right)\left(-5,3\right)=5,3\)

c)

\(\left(-2,5\right).\left(-4\right).\left(-7,9\right)=\left[\left(-\frac{5}{2}\right).\left(-4\right)\right]\left(-7,9\right)=10.\left(-7,9\right)=-79\)

d)

\(\left(-0,375\right).4\frac{1}{3}.\left(-2\right)^3=\left(-\frac{3}{8}\right).\frac{12}{3}.\left(-8\right)=12\)

a) (- 6,37 . 0,4) . 2,5

=  -6,37 . (0,4 . 2,5)

= -6,37 . 1

= -6,37

b) (-0,125 ) . (-5,3) . 8 

= ( - 0,125 . 8) . (-5,3)

= -1 . ( -5,3)

= 5,3

c) ( -2,5) . (-4) . (-7,9)

= ( -2,5 . -4) . (-7,9)

=  10 . (-7,9)

= -79

sao bạn tự hỏi tự tl

a: -3/4x12=-36/4=-9

b: \(=\dfrac{7}{15}\cdot\dfrac{10}{21}=\dfrac{7}{21}\cdot\dfrac{10}{15}=\dfrac{1}{3}\cdot\dfrac{2}{3}=\dfrac{2}{9}\)

c: \(=\dfrac{7}{18}\cdot\dfrac{12}{21}=\dfrac{12}{18}\cdot\dfrac{7}{21}=\dfrac{2}{3}\cdot\dfrac{1}{3}=\dfrac{2}{9}\)

d: \(=\dfrac{11}{15}\cdot\dfrac{5}{22}=\dfrac{11}{22}\cdot\dfrac{5}{15}=\dfrac{1}{2}\cdot\dfrac{1}{3}=\dfrac{1}{6}\)

e: \(=-\dfrac{8}{15}\cdot\dfrac{5}{4}=\dfrac{-40}{60}=\dfrac{-2}{3}\)

f: \(=-15\cdot\dfrac{3}{5}=-9\)