1) (-25).8.(-4).(-125)

= [(-25).4].[(-125).8]

=(-100).(-1000)

=100000

2)30.(5-10)

=30.5-30.10

=30.5-300

=150-300

=(-150)

3) 43.(53-81)+53.(81-43)

=43.53-43.81+53.81-53.43

=(43.53-53.43)+(43.81-53.81)

=0+81.(43-53)

=(-810)

4) Mk chưa biết làm nha

1) (-25).8.(-4).(-125)

= [ (-25) . (-4) ] . [ 8 . (-125) ]

= 100 . (-1000)

= -100 000

2) 30.(-5-10)

= 30 . (-15)

= -450

3) 43.(53-81)+53.(81-43)

= 43 . 53 - 43 . 81 + 53 . 81 - 53.43

= -43 . 81 + 53 . 81

= 81 . ( -43 + 53)

= 81 . 10

= 810

4) (-6)².(-17)+23.(-36)-72.30

= 36 . (-17) + 23 . (-36) - 72. 30

= (-36) . 17 + 23 . (-36) - 72 . 30

= (-36) . ( 17 + 23 ) - 72 . 30

= (-36) . 40 - 72.30

=  (-1440 )- 2160

= -3600

# HOK TỐT #

1) (-25).8.(-4).(-125)

=[-25.(-4)].[8.(-125)]

=100.(-1000)

=-100000

2) 30.(-5-10)

=30.(-15)

=-450

3) 43.(53-81)+53.(81-43)

=43.(-28)+53.38

=-1176+2014

=838

4) (-6)².(-17)+23.(-36)-72.30

=36.(-17)+23.(-36)-72.30

=36.(-17)+(-23).36-72.30

=36.[-17+(-23)]-72.30

=36.(-40)-72.30

=-1440-2160

=-3600

\(A=49\frac{8}{23}-\left(5\frac{7}{32}+14\frac{8}{23}\right)\)

\(A=49\frac{8}{23}-5\frac{7}{32}+14\frac{8}{23}\)

\(A= \left(49\frac{8}{23}-14\frac{8}{23}\right)-5\frac{7}{32}\)

\(A=\left[\left(49-14\right)-\left(\frac{8}{23}-\frac{8}{23}\right)\right]-5\frac{7}{32}\)

\(A=\left[35-0\right]-5\frac{7}{32}\)

\(A=35-5\frac{7}{32}\)

\(A=\frac{953}{32}\)

\(B=71\frac{38}{45}-\left(43\frac{38}{45}-1\frac{17}{57}\right)\)

\(B=71\frac{38}{45}-\frac{36377}{855}\)

\(B=\frac{1670}{57}\)

\(C=\left(19\frac{5}{8}:\frac{7}{12}-13\frac{1}{4}:\frac{7}{12}\right):\frac{4}{5}\)

\(C=\left[\left(19\frac{5}{8}-13\frac{1}{4}\right):\frac{7}{12}\right]:\frac{4}{5}\)

\(C=\left[\frac{51}{8}:\frac{7}{12}\right]:\frac{4}{5}\)

\(C=\frac{153}{14}:\frac{4}{5}\)

\(C=\frac{765}{56}\)

\(D=\left[\left(\frac{10}{15}-\frac{2}{3}\right):\frac{1}{7}\right]\cdot0,15-\frac{1}{4}\)

\(D=\left[0:\frac{1}{7}\right]\cdot\frac{3}{20}-\frac{1}{4}\)

\(D=0\cdot\frac{3}{20}-\frac{1}{4}\)

\(D=0-\frac{1}{4}\)

\(D=-\frac{1}{4}\)

\(E=\frac{13}{30}+\frac{28}{45}\cdot2\frac{1}{2}-\left[\left(\frac{1}{2}+\frac{1}{3}\right):\frac{53}{90}\right]:\frac{50}{53}\)

\(E=\frac{13}{30}+\frac{28}{45}\cdot\frac{5}{2}-\left[\frac{5}{6}:\frac{53}{90}\right]:\frac{50}{53}\)

\(E=\frac{13}{30}+\frac{28}{45}\cdot\frac{5}{2}-\frac{75}{53}:\frac{50}{53}\)

\(E=\frac{13}{30}+\frac{14}{9}-\frac{3}{2}\)

\(\)\(E=\frac{22}{45}\)

CHUC BAN HOC TOT >.<

1+2+3+4+5+6+7+8+9+10=55

11+12+13+14+15+16+17+18+19+20=155

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+30-50-53=362

1+2+3+4+5+6+7+8+9+10=55

11+12+13+14+15+16+17+18+19+20=155

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+30-50-53=362

Tính nhanh:

   912 + [88 + (-453) + (-547)]

= 912 + 88 - 453 - 547

= (912 + 88) - (453 + 547)

= 1000 - 1000

= 0

Thực hiện các phép tính sau:

6-8 = 6 + (-8) = -2

3-(-9) = 3 + 9 = 12

(-5)-10 = (-5) + (-10) = -15

0-7 = -7

4-0 = 4

(-2)-(-10) = (-2) + 10 = 8

Tính:

-2+(-6)+7- 3 = -4

-5-7-3+7 = -8

(-6)-4+5-7+12 = 0

2-(-8)+10-30 = -10

Bỏ dấu ngoặc rồi tính:

a) (4+32+6)+(10-36-6)

= 4 + 32 + 6 + 10 - 36 - 6

= (4 + 32 - 36) + (6 - 6) + 10

= 0 + 0 + 10

= 10

b) (77+22+-65)-(67+12-75)

= 77 + 22 - 65 - 67 - 12 + 75

= (77 - 67) + (22 - 12) - (65 - 75)

= 10 + 10 - (-10)

= 30

c)-(-21+43+7)-(11-53-17).

= 21 - 43 - 7 - 11 + 53 + 17

= (21 - 11) - (43 - 53) - (7 - 17)

= 10 - (-10) - (-10)

= 30

Tham khảo nha!!!

6A6. PHIẾU BÀI TẬP TUẦN 12
Bài 1. Biểu diễn các hiệu sau thành tổng rồi tính:
a) ( ) 23 12−− b) ( ) 43 53−−
c) ( ) ( ) 15 17 − − − d) 14 20 −
Bài 2. Tính nhanh
a) (2354 − 45) − 2354 b) (−2009) −(234 − 2009)
c) (16 + 23) + (153−16 − 23)
Bài 3. Tìm số nguyên x, biết:
a) ( ) 3155x −=−− b) 14 32 26 x − − + = −
c) x + (−31) −(−42) = −45 d) (−12) −(13− x) = −15− (−17).
Bài 4: Tìm x biết:
a, ( ) 2670x −−−= . b, ( ) ( ) 7 5 3 x + = − + − . c, ( ) 11811x −=−− .
d, 30 + (32 − x) =10 . e, x +12 + (−5) = −18 . g, 3− x = −21−(−9) .
Bài 5. Tìm số nguyên x, biết:
a) x − 43 = (35− x) − 48 b) 305− x +14 = 48+ ( x − 23)
c) −( x − 6 +85) = ( x + 51) − 54 d) −(35− x) − (37 − x) = 33− x
Bài 6.Tính tổng đại số sau một cách hợp lí
a) 7 −8 + 9 −10 +11−12 +...+ 2009 − 2010
b) −1− 2 − 3− 4 −...− 2009 − 2010
c) 1− 3− 5 + 7 + 9 −11−13+15 +....+ 2017 − 2019 − 2021+ 2023
Bài 7. Điền số thích hợp vào bảng sau
a 13 5 − 12− 10 − 10 − 12
b 21 3 17 − 10 − 10 − 12−
a + b −8 8
Bài 8. Tính nhanh
a) 215+ 43+ (−215) + (−25) b) (−312) + (−327) + (−28) + 27
c) (134 −167 + 45) − (134 + 45)
Bài 9. So sánh
a) 125 và 125+ (−2) b) −13 và (−13) + 7 c) −15 và (−15) + (−3)
Bài 10. Điền số thích hợp vào bảng sau:
a 3− 7− 8 0
b 8 −16 23 −27
ab−
a−
b−
…………………………….……….Hết………………………………

a) Ta có:

C = 5/18 + 8/19 - 7/21 + (-10/36 + 11/19 + 1/3) - 5/8

C = 5/18 + 8/19 - 1/3 - 5/18 + 11/19 + 1/3 - 5/8

C = (5/18 - 5/18) + (8/19 + 11/19) - (1/3  - 1/3) - 5/8

C = 1 - 5/8

c = 3/8

b) F = 15/14 - (17/23 - 80/87 + 5/4) + (17/23 - 15/14 + 1/4)

F = 15/14 - 17/23 + 80/87 - 5/4 + 17/23 - 15/14 + 1/4

F = (15/14 - 15/14) - (17/23 - 17/23) + 80/87 - (5/4 - 1/4)

F = 80/87 - 1

F = -7/87

c) G = 1/25 - 4/27 + (-23/27 + -1/25 - 5/43) + 5/43 - 4/7

G = 1/25 - 4/27 - 23/27 - 1/25 - 5/43 + 5/43 - 4/7

G = (1/25 - 1/25) - (4/27 + 23/27) - (5/43 - 5/43) - 4/7

G = -1 - 4/7 = -11/7