a) 47 x 9 = 47 x (10 -1)

= 47 x 10 - 47 x 1 = 470 -47 = 423

24 x 99 = 24 x ( 100 -1)

= 24 x 100 - 24 x 1 = 2400 - 24 = 2376

b) 138 x 9 = 138 x (10 -1)

= 138 x 10 - 138 x 1 = 1380 - 138 = 1242

123 x 99 = 123 x (100 -1)

= 123 x 100 - 123 x 1 = 12300 - 123 = 12177

đung hết rồi

\(C,\dfrac{1}{2}.\dfrac{3}{4}+\dfrac{1}{2}.\dfrac{1}{4}=\dfrac{1}{2}.\left(\dfrac{3}{4}+\dfrac{1}{4}\right)\)

\(=\dfrac{1}{2}.\dfrac{4}{4}=\dfrac{1}{2}.1=\dfrac{1}{2}\)

\(D,\dfrac{11}{3}.\dfrac{26}{7}-\dfrac{26}{7}.\dfrac{8}{3}=\dfrac{26}{7}.\left(\dfrac{11}{3}-\dfrac{8}{3}\right)\)

\(=\dfrac{26}{7}.\dfrac{3}{3}=\dfrac{26}{7}.1=\dfrac{26}{7}\)

  \(\dfrac{26}{7}\) x \(\dfrac{11}{3}-\dfrac{26}{7}\) x \(\dfrac{2}{3}-\dfrac{6}{3}\) x \(\dfrac{26}{7}\)

\(=\dfrac{26}{7}\) x \(\left(\dfrac{11}{3}-\dfrac{2}{3}-\dfrac{6}{3}\right)\)

\(=\dfrac{26}{7}\) x \(\dfrac{3}{3}\)

\(=\dfrac{26}{7}\) x \(1=\dfrac{26}{7}\)

26/7 x 11/3 - 26/7 x 2/3 - 6/3 x 26/7

=( 11/3 - 2/3 - 6/3 ) x26/7

=      1 x 26/7

=         26 /7

Tick cho mình nha

26 x 4 + 52 + 3 x 26 + 26

= 104 + 52 + 78 + 26

= ( 52 + 78 ) + ( 104 + 26 )

= 130 + 130

= 260

   26 x 4 + 52 + 3 x 26 + 26

= 104 + 52 + 78 + 26 

= ( 104 + 26 )  + ( 52 + 78 )

= 130 + 130

= 260

Học tốt nha

174 x 36 - 174 x 26
= 174 x ( 36 - 26 )
= 174 x 10
= 1740

2/3 x 4/5 + 1/8 x 2/3
= 2/3 x ( 4/5 + 1/8 )
= 2/3 x 37/40
= 37/60

`=174xx(36-26)`

`=174xx10=1740`

`=2/3xx(4/5+1/8)`

`=2/3xx37/40=37/60`

X:15/26=2/5

X = 2/5 x 15/26

X = 3/13

4/5 nhân x= 10/11:3/4

4/5 x X = 10/11 x 4/3

4/5 x X = 40/33

X = 40/33 : 4/5

X = 50/33

26*8+2*2*13-10*26

=26*8+2*26-10*26

=26*(8+2-10)

=26*0

=0

Nhớ tick mik nha

8/5

686/65

5/7

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