a.45+45+45+45+15+15+15+15=45×4+15×4=4×(45+15)=4×60=240

125+125+125+125-25-25-25-25=125×4-25×4=4×(125-25)=4×100=400

5+ 5 + 5 + 5+ 5 + 5 +5+ 5 + 5 +5=5x10=50

25 + 25 + 25 + 25 + 25 + 25 +25 + 25=25x8=200

45 + 45 + 45 + 45 + 15 + 15 + 15 + 15=(45x4)+(15x4)=180+60=240

5+ 5 + 5 + 5+ 5 + 5 +5+ 5 + 5 +5
= 5 x 10
= 50

25 + 25 + 25 + 25 + 25 + 25 +25 + 25
= 25 x 8
= 200

45 + 45 + 45 + 45 + 15 + 15 + 15 + 15
= 45 x 4 + 15 x 4
= 180 + 60
= 240

2 + 4 + 6 + 8 + 10 + 12 + 14 + 16 + 18
= (2 + 18) + (4 + 16) + (8 + 12) + (6 + 14) + 10
= 20 + 20 + 20 + 20 + 10 
= 20 x 4 + 10
= 80 + 10
= 90 

125 + 125 + 125 + 125 - 25 - 25 - 25 - 25 
= 4 x (125 - 25) 
= 4 x 100 
= 400
(Tick cho mk pls ^^)

1 : Tính nhanh:

a) 2376 + 3425 - 376 - 425 = ( 2376 - 376 ) + ( 3425 - 425 )

                                       = 2000 + 3000

                                       = 5000

b)4638 - 2437 + 5362 - 7563 = 2210 + ( - 2210 )

                                          = 0

c) 45 + 45 + 45 + 45 + 15 + 15 + 15 + 15

  = 45 x 4 + 15 x 4

 = ( 45 + 15 ) x 4

 = 60 x 4

 = 240

d) 4 x 125 x 25 x 8 = ( 4 x 25 ) x ( 125 x 8 )

                            = 100 x 1000

                            = 100000

e) 2 x 8 x 50 x 25 x 125 = ( 2 x 50 ) x ( 8 x 125 ) x 25

                                   = 100 x 1000 x 25

                                   = 100000 x 25

                                   = 2500000

2 : Tính nhanh bằng 2 cách:

C1 : 125 + 125 + 125 + 125 - 25 - 25 - 25 - 25

    = ( 125 - 25 ) + ( 125 - 25) + ( 125 - 25 ) + ( 125 - 25 )

    =100 + 100 + 100 + 100 

    = 100 x 4 

    = 400

C2 : 125 + 125 + 125 + 125 - 25 - 25 - 25 - 25

     = 125 x 4 - 25 x 4

     = ( 125 - 25 ) x 4

     = 100 x 4

     = 400

1.

a. 5000
b. 0

c. 240

d. 100000

e. 2500000

2.

400

1: Tính nhanh:

a, 2376 + 3425 - 376 - 425

 = ( 2376 - 376 ) + ( 3425 - 425 )

 = 2000 + 3000

 = 5000.

b, 4638 - 2437 + 5362 - 7563

 = 2210 + (-2210)

 = 0.

c, 45 + 45 + 45 + 45 + 15 + 15 + 15 + 15 + 15

 = ( 45 + 15 ) +  ( 45 + 15 ) +  ( 45 + 15 ) +  ( 45 + 15 ) 

 = 60 + 60 + 60 + 60

 = 240.

d, 4 x 125 x 25 x 8 

 = ( 4 x 25 ) x ( 125 x 8 )

 = 100 x 1000

 = 100000.

e, 2 x 8 x 50 x 25 x 125

 = ( 2 x 50 ) x ( 8 x 125 ) x 25

 = 100 x 1000 x 25

 = 2500000.

2: Tính nhanh bằng hai cách:

  125 + 125 + 125 + 125 - 25 - 25 - 25- 25

= ( 125 - 25 ) + ( 125 - 25 ) + ( 125 - 25 ) + ( 125 -25 )

= 100 + 100 + 100 + 100

= 400.

a) 17 x 25 + 25 x 33 +25 x 50 = 25 x (17 + 33 + 50)

                                               = 25 x 100 = 2500

b) 125 x 15 -25 x 15 = 15 x (125 - 25)

                              = 15 x 100 = 1500

a. 17.25+25.33+25.50

= 25.(17+33+50)

= 25.100

= 2500

b. 125.15-25.15

= 15.(125-25)

= 15.100

= 1500

a)17*25+25*33+25*50

=25 x (17+33+50)

=25 x 100

= 2500

b)125*15-25*15

=15 x (125-25)

=15 x 100

=1500

18 . 26 . 25 . 9

= ( 18 . 25 ) . ( 26 . 9 )

= 450 . 234

= 105 300

2 . 450 . 25 . 8

= ( 2 . 450 ) . ( 25 . 8 )

= 900 . 200

= 180 000

55 . 17 .16 . 15

( 15 . 16 ) . ( 55 . 17 )

= 240 . 935

= 224 400

125 . 98 . 2 . 8 . 25

( 25 .8 ) . ( 125 . 2 ) . 98

= 200 . 250 . 98

= 50 000 . 98

= 4 900 000

15 . 6 . 4 . 125 . 8

= ( 125 . 4 ) . ( 15 . 8 ) . 6

= 500 . 120 . 6

= 60 000 . 6

= 36 000

chúc bạn may mắn . tick cho mình nhé !

a: \(=\left(18\cdot25\right)\cdot9\cdot26=234\cdot450=105300\)

b: \(=\left(25\cdot8\cdot2\right)\cdot450=400\cdot450=180000\)

c: \(=\left(55\cdot17\right)\cdot16\cdot15=240\cdot935=224400\)

d: \(=125\cdot8\cdot2\cdot25\cdot98=98\cdot50\cdot1000=4900000\)

e: \(=125\cdot8\cdot15\cdot4\cdot6=1000\cdot360=360000\)

18 . 26 . 25 . 9

= ( 18 . 25 ) . ( 26 . 9 )

= 450 . 234

= 105 300

2 . 450 . 25 . 8

= ( 2 . 450 ) . ( 25 . 8 )

= 900 . 200

= 180 000

55 . 17 .16 . 15

( 15 . 16 ) . ( 55 . 17 )

= 240 . 935

= 224 400

125 . 98 . 2 . 8 . 25

( 25 .8 ) . ( 125 . 2 ) . 98

= 200 . 250 . 98

= 50 000 . 98

= 4 900 000

15 . 6 . 4 . 125 . 8

= ( 125 . 4 ) . ( 15 . 8 ) . 6

= 500 . 120 . 6

= 60 000 . 6

= 36 000

chúc bạn may mắn . tick cho mình nhé !