\(\begin{array}{*{20}{c}}{a)\,\,}\\{}\\{}\end{array}\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{28}\\{35}\end{array}}\\\hline{\,\,\,\,63}\end{array}\)                      \(\begin{array}{*{20}{c}}{ - \begin{array}{*{20}{c}}{63}\\{28}\end{array}}\\\hline{\,\,\,\,35}\end{array}\)                     \(\begin{array}{*{20}{c}}{ - \begin{array}{*{20}{c}}{63}\\{35}\end{array}}\\\hline{\,\,\,28}\end{array}\)

\(\begin{array}{*{20}{c}}{b)\,\,}\\{}\\{}\end{array}\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{42}\\{49}\end{array}}\\\hline{\,\,\,\,91}\end{array}\)                     \(\begin{array}{*{20}{c}}{ - \begin{array}{*{20}{c}}{91}\\{42}\end{array}}\\\hline{\,\,\,49}\end{array}\)                       \(\begin{array}{*{20}{c}}{ - \begin{array}{*{20}{c}}{91}\\{49}\end{array}}\\\hline{\,\,\,\,42}\end{array}\)

\(65-\left(-35\right)+\left(27-49\right)+\left(-28\right)\)

\(=65+35+27-49-28\)

\(=100+27-49-28\)

\(=127-\left(49+28\right)\)

\(=127-77=50\)

65-(-35)+(27-49)+(-28)

= 65 + 35 - 22 + (-28)

= 100 -22 +(-28)

= 78+(-28)

= 50

\(65-\left(-35\right)+\left(27-49\right)+\left(-28\right)\)

\(=65+35+27-49-28\)

\(=100+27-49-28\)

\(=127-49-28\)

\(=78-28\)

\(=50\)

_Chúc bạn học tốt_

\(\)

hỏi chơi à?

4/5*5/24*1 và 1/7

miru

Rút gọn rồi tính: 

\(\frac{28}{35}.\frac{15}{72}.1\frac{7}{49}\)

\(=\frac{4}{5}.\frac{5}{24}.\frac{56}{49}\)

\(=\frac{4.5.8}{5.24.7}=\frac{4}{21}\)

\(\frac{28}{35}.\frac{15}{72}.1\frac{7}{49}\)

\(=\frac{4}{5}.\frac{5}{24}.\frac{7}{49}\)

\(=\frac{4}{21}\)

k mk nha, cảm ơn những người đã k

\(\dfrac{24}{35}:\dfrac{15}{7}=\dfrac{24}{35}\times\dfrac{7}{15}=\dfrac{8}{25}\)

\(\Rightarrow chọn\) \(B\)

`# \text {DNamNgV}`

\(\dfrac{24}{35} \div \dfrac{15}{7} \\ = \dfrac{24}{35} \times \dfrac{7}{15} \\ = \dfrac{8}{25}\)

Chọn đáp án B.

\(\frac{28}{35}\times\frac{15}{72}\times1\frac{7}{49}=\frac{4}{5}\times\frac{5}{24}\times\frac{8}{7}=\frac{160}{840}=\frac{4}{21}\)

a) 7 x 5 = 35       7 x 6 = 42       7 x 8 = 56       7 x 4 = 28

    35 : 7 = 5       42 : 7 = 6       56 : 7 = 8       28 : 7 = 4

b) 42 : 7 = 6       35 : 7 = 5       63 : 7 = 9       16 : 2 = 8

    14 : 7 = 2       49 : 7 = 7       7 : 7 = 1       48 : 6 = 8

    28 : 7 = 4       70 : =10       21 : 7 = 3       56 : 7 = 8

 7 X 5 = 35

14 x 32 + 7x 140 - 28

= 14 x 32 + 7 x 14 x 10 - 14 x 2

= 14 x 32 + 14 x 70 - 14 x 2

= 14 x ( 32 + 70 - 2 )

= 14 x 100

= 1400

17 x 35 + 67 x 17 - 34

= 17 x 35 + 67 x 17 - 2 x 17

= 17 x ( 35 + 67 - 2 )

= 17 x 100

= 1700

17 x 35 + 67 x 17 - 34

= 17 x (35 + 67) - 34

= 17 x 102 - 34

= 1734 -  34

= 1700

14 x 32 + 7x 140 - 28

= 14 x 32 + 7 x 14 x 10 - 14 x 2

= 14 x 32 + 14 x 70 - 14 x 2

= 14 x ( 32 + 70 - 2 )

= 14 x 100

= 1400

17 x 35 + 67 x 17 - 34

= 17 x 35 + 67 x 17 - 2 x 17

= 17 x ( 35 + 67 - 2 )

= 17 x 100

= 1700

  35 x 12 - 15 x 28 + \(\frac{2323}{4949}-\frac{23}{49}\)+ 2010 

=  (420 - 420 )+ \(\left(\frac{23}{49}-\frac{23}{49}\right)\)+ 2010

= 0 + 0 + 2010 = 2010 .

35 x 12 -15 x28+2323/4949-23/49+2010

=35x12-15x28+23/49-23/49+2010

=420-420+0+2010

=0+0+2010

=2010

35.12-15.28+ 23.101/49.101-23/49+2010=

=7.5.4.3 - 3.4.4.7+23/49-23/49+2010=

=2010

a) 35 + 21 + 49 = 105 

=> 105 = 21 x 5

b) 63 + 14 + 28 = 105

=> 35 x 3 

k mik nha mn làm ơn nha

a ) 35 + 21 + 49

= 35 + ( 21 + 49 )

= 35 + 70

= 105

b ) 63 + 21 + 49

= 63 + ( 21 + 49 )

= 63 + 70

= 133