nhiều quá mk phụ bạn chút thôi

a)47*(23+50)-23*(47+50)=47*23+47*50-23*47+23*50=(47*23-23*47)+(47*50+23*50)=(47+23)*50=70*50=3500

b)29*(85-47)+85*(47-29)=29*85-29*47+85*47-85*29=(29*85-85*29)+(85*47-29*47)=(85-29)*47=56*47=2632

c)37*90-37*(-10)=37*[90-(-10)]=37*100=3700

a. 47.[23+50]-23.[47+50]

=47.73-23.97

=3431-2231

=1200

b,29.[85-47]+85.[47-29]

=29.38+85.18

=1102+1520

=-428

c,37.90-37.[-10]

=37.(90-(-10))

=37.100

=3700

d,15.12-3.5.10

=15.12-15.10

=15.(12-10)

=15.2

=30

e,29.[19-13]-19.[29-13]

=29.6-19.16

=174-304

=-130

f,33.[17-5]-17.[33-5]

=33.12-17.32

=396-544

=-148

g,54-6.[17+9]

=54-6.26

=54-156

=-102

h,1000+[-570]+2341+[-430]

=430+2341+(-430)

=(-430+430)+2341

=0+2341

=2341

a. \(\left(-37\right)+14+26+37\)

\(=\left[\left(-37\right)+37\right]+\left(14+26\right)\)

\(=0+40\)

\(=40\)

b. \(\left(-24\right)+6+10+24\)

\(=\left[\left(-24\right)+24\right]+6+10\)

\(=0+6+10\)

\(=16\)

c. \(15+23+\left(-25\right)+\left(-23\right)\)

\(=\left[\left(-25\right)+15\right]+\left[\left(-23\right)+23\right]\)

\(=-10+0\)

\(=-10\)

các câu khác bn tự lm

d. \(35\cdot18-5\cdot7\cdot28\)

\(=35\cdot18-35\cdot28\)

\(=35\cdot\left(18-28\right)\)

\(=35\cdot\left(-10\right)\)

\(=-350\)

câu e, f, g bn tự lm

\(A=\frac{1}{1\cdot2}+\frac{2}{2\cdot4}+\frac{3}{4\cdot7}+\frac{4}{7\cdot11}+...+\frac{10}{46\cdot56}\)

\(A=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+...+\frac{1}{46}-\frac{1}{56}\)

\(A=1-\frac{1}{56}\)

\(A=\frac{55}{56}\)

\(B=\frac{4}{3\cdot7}+\frac{4}{7\cdot11}+\frac{4}{11\cdot15}+...+\frac{4}{23\cdot27}\)

\(B=\frac{1}{3}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+\frac{1}{11}-\frac{1}{15}+...+\frac{1}{23}-\frac{1}{27}\)

\(B=\frac{1}{3}-\frac{1}{27}\)

\(B=\frac{8}{27}\)

\(C=\frac{4}{3\cdot6}+\frac{4}{6\cdot9}+\frac{4}{9\cdot12}+...+\frac{4}{99\cdot102}\)

\(C=\frac{4}{3}\left(\frac{3}{3\cdot6}+\frac{3}{6\cdot9}+\frac{3}{9\cdot12}+...+\frac{3}{99\cdot102}\right)\)

\(C=\frac{4}{3}\left(\frac{1}{3}-\frac{1}{6}+\frac{1}{6}-\frac{1}{9}+\frac{1}{9}-\frac{1}{12}+...+\frac{1}{99}-\frac{1}{102}\right)\)

\(C=\frac{4}{3}\left(\frac{1}{3}-\frac{1}{102}\right)\)

\(C=\frac{4}{3}\cdot\frac{33}{102}\)

\(C=\frac{22}{51}\)

Các bạn giải giúp mình nha😐

300

300

= 300 

Em nến gõ bằng công thức toán học em nhé. Như vậy mọi người nới hiểu đúng đề bài để trợ giúp cho em một cách tốt nhất em ạ!

a) \(\dfrac{25}{37}\times\dfrac{18}{29}+\dfrac{18}{29}\times\dfrac{12}{37}\)

\(=\dfrac{18}{29}\times\left(\dfrac{25}{37}+\dfrac{12}{37}\right)\)

\(=\dfrac{18}{29}\times\dfrac{37}{37}\)

\(=\dfrac{18}{29}\times1\)

\(=\dfrac{18}{29}\)

b) \(\dfrac{31}{85}\times\dfrac{11}{19}+\dfrac{31}{85}\times\dfrac{12}{19}-\dfrac{42}{19}\times\dfrac{31}{85}\)

\(=\dfrac{31}{85}\times\left(\dfrac{11}{19}+\dfrac{12}{19}-\dfrac{42}{19}\right)\)

\(=\dfrac{31}{85}\times\dfrac{-19}{19}\)

\(=\dfrac{31}{85}\times-1\)

\(=-\dfrac{31}{85}\)

c) \(\dfrac{16}{53}:\dfrac{17}{9}-\dfrac{16}{53}:\dfrac{17}{8}\)

\(=\dfrac{16}{53}:\left(\dfrac{9}{17}-\dfrac{8}{17}\right)\)

\(=\dfrac{16}{53}:\dfrac{1}{17}\)

\(=\dfrac{16}{901}\)

c) \(\dfrac{1}{5}\times\dfrac{12}{31}\times\dfrac{4}{3}+\dfrac{19}{31}\times\dfrac{4}{15}\)

\(=\dfrac{4}{15}\times\dfrac{12}{31}+\dfrac{19}{31}\times\dfrac{4}{15}\)

\(=\dfrac{4}{15}\times\left(\dfrac{12}{31}+\dfrac{19}{31}\right)\)

\(=\dfrac{4}{15}\times\dfrac{31}{31}\)

\(=\dfrac{4}{15}\times1\)

\(=\dfrac{4}{15}\)

a: =18/29*(25/37+12/37)

=18/29

b: =31/85(11/19+12/19-42/19)

=-31/85

c; =16/53(9/17+8/17)=16/53

d: =4/15(12/31+19/31)=4/15

áp dụng kiến thức tính nhanh ý

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50=1275

= 1275

=1275

=1245

Có ai rảnh đâu mà đi ngồi cộng ngần đấy số ra.