1) 42/35 - [ 33/14 . 21/22 - ( 54/25 : 27/25 - 7/10 )]

= 42/35 - ( 9/4-13/10)

=42/35-19/20

=1/4

2) a) 5/21 . x/34 = 35/102     

x/34=35/102 : 5/21

x/34=49/34

=> x=34

Vậy x=34

b) 15/x . 21/13 = 45/91

15/x=45/91 : 21/13

15/x=15/49

=> x=49

Vậy x=49

lớp 4

a. 64 x 25 + 35 x 25 + 25

= 64 x 25 + 35 x 25 + 25 x 1

= 25 x ( 64 + 35 + 1 )

= 25 x 100 

= 2500

b. 58 x 42 + 32 x 8 + 5 x 16

c. ( 42 x 43 + 57 x 43 + 43 ) - 360 : 4

= 42 x 43 + 57 x 43 + 43 x 1 - 90

= 43 x ( 42 + 57 +1 ) - 90

= 43 x 100 - 90

= 4300 - 90

= 4210

d. 456 : 2 x 181456 : 3 - 102

Trả lời:

a,\(64\times25+35\times25+25\)

\(=25\times\left(64+35+1\right)\)

\(=25\times100\)

\(=2500\)

b,\(58\times42+32\times8+5\times16\)

\(=2436+256+80\)

\(=2772\)

c,\(\left(42\times43+57\times43+43\right)-360\div4\)

\(=43\times\left(42+57+1\right)-90\)

\(=43\times100-90\)

\(=4300-90\)

\(=4210\)

d,\(456\div2\times181456\div3-102\)

\(=228\div3\times181456-102\)

\(=76\times181456-102\)

\(=13790656-102\)

\(=13790554\)

a,64 x 25 + 35 x 25 +25

=25x(64+35+1)

=25x100

=250

b, 58 x 42 +32 x 8 +5 x 16

=2772

c,(42 x 43 +57 x 43+43 )-360:4

=43x(42+57+1) - 360 :4

= 43 x 100 -90

=4300-90

=4210

d,456:2 x 181456:3 -102

=228x181456:3-102

=13790656-102

=13790554

a)64x25+35x25+25=25x(64+35)+25=25x99+25=2475+25=2500

mình trả lời ý a

64 x 25 +35 x 25 +25 x 1

= 25 x ( 64 + 35 + 1 )
= 25 x 100

= 2500

Tính nhanh:

a) 64 x 25 + 35 x 25 + 25 

= 64 x 25 + 35 x 25 + 25 x 1

= 25 x ( 64 + 35 + 1 )

= 25 x 100

= 2500

  b) 58 x 42 + 32 x 8 + 5 x 16

= 

= 0

( 5 + 10 + 15 + 20 + 25 + 30 + 35 ) x ( 42 - 6 x 7 ) 

= ( 5 + 10 + 15 + 20 + 25 + 30 + 35 ) x ( 42 - 42 )

= ( 5 + 10 + 15 + 20 + 25 + 30 + 35 ) x 0

= 0

=0 nha

1.
=(25x4)x(96x2)
=100x192=19200
2.
=155x(42+58)
=155x100=1500
3.
=35x(461+539)
=35x1000=35000
4
=196x(73+27)
=196x100=19600

ủa ;-;

sao ko cách dòng dc ta

15 + 12+  25 + 35 +42 +  25 = (15 + 25 + 35 + 25) + (12 + 42) = 100 + 54 = 154   

=(15+35)+(25+25)+(12+42)

=50+50+54

=154

số đó là

256

ai muốn k

thì k tui đã

25 + 62 +35 + 42 + 92 = 256

k mk nha

số đó là

256

ai muốn k thì 

k tui đã

a/ ( 35-x)-25=40-(15-18)

     (35-x)-25=40-(-3)

      (35-x)-25=43

          35-x=43+25

           35-x=68

              x=35-68

              x= -33

b/ x+42=-15+27: 3^2

   x+42=-15+27 : 9

    x+42=-15+3

      x+42=-12

            x=-12 -42

             x= -54

a) (35-x)-25=40-(15-18)

     (35-x)-25=43

     35-x=43-25=18

      x=35-18=17

b)x+42=(-15)+27:3^2

   x+42=-12

   x= (-12)-42

      x=-54

c)27-(5-|x|)=31

        5-|x|=27-31=-4

         |x|=5-(-4)

        |x|=9

=>x=9 hoặc -9

1 < 2

3 > 1 

3 < 4

3 = 3

5 > 2

5 > 4

2 < 3

1 < 5

4 > 1

4 = 4

4 > 3

5 = 5

2 < 3

3 < 5

1 < 4

3 > 1