a) |-15+6| = |-9| = 9

b) |-25 + (-17)| = |-42| =  42

c) | -36 +  15| = |-21| = 21

d) |-21 + 49| = | 48| = 48

e) |-21+49| = |48| = 48 

g) |43 + (-28) | = | 15|  = 15

h) |-23 + 33|  = |10| = 10

i) |-46 + (-29) | = | -75| = 75

a) 9/22 x 33/18 =3/4

b) 12/35 : 36/25 = 5/21

c) 19/17 : 76/51 =3/4

a) \(\frac{9}{22}\times\frac{33}{18}\)

\(=\frac{9}{22}\times\frac{11}{6}\)

\(=\frac{9\times11}{22\times6}=\frac{3}{4}\)

b) \(\frac{12}{35}:\frac{36}{25}=\frac{12}{35}\times\frac{25}{36}\)

                     \(=\frac{5}{21}\)

c) \(\frac{19}{17}:\frac{76}{51}=\frac{19}{17}\times\frac{51}{76}\)

                      \(=\frac{3}{4}\)

\(a,\frac{9}{22}x\frac{33}{18}\)

\(=\frac{3.3.11.3}{11.2.3.3.2}\)

\(=\frac{3}{2.2}\)

\(=\frac{3}{4}\)

\(b,\frac{12}{35}:\frac{36}{25}\)

\(=\frac{12}{35}.\frac{25}{36}\)

\(=\frac{12.25}{35.36}\)

\(=\frac{12.5.5}{5.7.12.3}\)

\(=\frac{5}{7.3}\)

\(=\frac{5}{21}\)

\(c,\frac{19}{17}:\frac{76}{51}\)

\(=\frac{19}{17}.\frac{51}{76}\)

\(=\frac{19.51}{17.76}\)

\(=\frac{19.17.3}{17.19.4}\)

\(=\frac{3}{4}\)

Ai đúng mình like !

\(a,\dfrac{1}{7}+\dfrac{1}{3}=\dfrac{3}{21}+\dfrac{7}{21}=\dfrac{10}{21}\\ b,\dfrac{-2}{3}+\dfrac{-5}{7}=\dfrac{-14+\left(-15\right)}{21}=\dfrac{-29}{21}\\ c,\dfrac{1}{2}-\dfrac{-1}{2}-\dfrac{1}{3}=\dfrac{3+3-2}{6}=\dfrac{4}{6}=\dfrac{2}{3}\)

\(a.\dfrac{4}{28}+\dfrac{12}{36}=\dfrac{1}{7}+\dfrac{1}{3}=\dfrac{3}{21}+\dfrac{7}{21}=\dfrac{10}{21}\\ b.\dfrac{-12}{18}+\dfrac{-15}{21}=\dfrac{-2}{3}+\dfrac{-5}{7}=\dfrac{-14}{21}+\dfrac{-15}{21}=\dfrac{-29}{21}\\ c.\dfrac{14}{28}+\dfrac{16}{32}-\dfrac{17}{51}=\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{17}{51}=1-\dfrac{17}{51}=\dfrac{2}{3}\)

\(\dfrac{4}{28}+\dfrac{12}{36}=\dfrac{144}{1008}+\dfrac{336}{1008}=\\ \dfrac{480}{1008}=\dfrac{10}{21}\)

Câu b và c em làm tương tự.

a) (-12) + 25 + 75 + 12 = (-12) + 12 + 25 + 75 = 0 +100 = 100.

b) 60 +12 + (-17) + (-43) = 60 + [(-47) + (-43)] +12.

c) (-2) + (-87) + (-18) + 87 = [(-2) + (-18)] + [(-87) + 87].

d) (-1)+(-2) + 36 + (-17) = 36+[(-1) + (-2) + (-17)].

a, (-12) + 25 + 75 + 12

= [ (-12) + 12] + (25 + 75)

= 0 + 100

= 100

b, 60 + 12 + (-17) + (-43)

= -(17 + 43) + 60 + 12

= - 60 + 60  + 12

= 0 + 12

= 12

a) 2459 - ( 400 + 459 )

= 2459 - 400 - 459

= 2000 - 400 

= 1600

b) 435 x 25 +76 x 435 - 435

= 435 x 25 + 76 x 435 - 435 x 1

= 435 ( 25 + 76 - 1 )

= 435 x 100

= 43500

c) 36 x 49 + 51 x 36

= 36 ( 49 + 51 )

= 36 x 100

= 3600

sao câu nào Ngọc Nguyễn Minh cũng được l-i-k-e thế

a) 2459 - ( 400 + 459 )

= 2459 - 400 - 459

= (2459 - 459 ) - 400

= 2000 - 400

= 1600  (L~I~K~E)

Cái * là nhân

b) 435 * 25 +76 * 435 - 435

= 435 *25 +76 * 435 - 435 * 1

= 435 * ( 25 + 76 - 1 )

= 435 * ( 101 -1 )

= 435 * 100

= 43500       (L~I~K~E)

c) 36 * 49 + 51 * 36

= 36 * ( 49 + 51 )

= 36 * 100

= 3600           (L~I~K~E)