8/5

686/65

5/7

can loi giai

Bài 4:
tích của số lớn nhất có ba chữ số khác nhau và số bé nhất có ba chữ số khác nhau là:

\(987\times102=100674\)

Bài 5:

a) 435 x 27 + 13 x 435 =435x(27+13)=435x30=13050
b) 213 x 115 – 213 x 15=213x(115-15)=213x100=21300
c) 25 x 433 x 4=(25x4)x433=100x433=43300

Bài 4: 

987x102=100674

`a,`

`34,67+5,42+4,58`

`= 34,67+(5,42+4,58)=34,67+10=44,67`

`b,`

`15,27 \times 2 \times 0,5`

`= 15,27 \times (2 \times 0,5)`

`= 15,27 \times 1=15,27`

`c,`

`45,28 \times 45 + 45,28 \times 55`

`= 45,28 \times (45+55)`

`= 45,28 \times 100=4528`

a.

34,67 + 5,42 + 4,58

= (34,67 + 5,42) + 4,58= 40,09 + 4,58 = 44,67 

b. 15,27 x 2 x 0.5

= (15,27 x 2) x 0.5 = 30,54 x 0,5 = 15,27

c. 45,28  x45 + 45,28 x 55

=  45,28 x (45 + 55)

= 45,28 x 100 = 4528

a: \(17,5\cdot4\cdot3\cdot25\)

\(=17,5\cdot3\cdot\left(4\cdot25\right)\)

\(=52,5\cdot100=5250\)

b: \(25,6\cdot7,5+25,6\cdot2,5\)

\(=25,6\left(7,5+2,5\right)\)

\(=25,6\cdot10=256\)

c: \(4,52\cdot12,5-2,5\cdot4,25\)

\(=2,5\left(4,52\cdot5-4,25\right)\)

\(=2,5\cdot18,35=45,875\)

d: \(7,7\cdot9+7,7\)

\(=7,7\left(9+1\right)\)

\(=7,7\cdot10=77\)

a: =13/26*9/18*2/3=2/3*1/4=2/12=1/6

b: =44/22*5/15*3/2=2*1/3*3/2=2*1/2=1

a: =428(36+64)=42800

b: =512(47-37)=5120

c: =72x100=7200

\(428×(36+64)\)

\(=428×100\)

\(=42800\)

\(512×(47-37)\)

\(=512×10\)

\(=5120\)

\(72×(4×25)\)

\(=72×100\)

\(=7200\)

\(\left(\dfrac{4+5}{9}\right)\text{×}\dfrac{3}{7}\)

\(=1\text{×}\dfrac{3}{7}\)

\(=\dfrac{3}{7}\)

a) 4 x 78 x 5

= (4 x 5) x 78

= 20 x 78

= 1560

b) 2 x 99 x 5

= (2 x 5) x 99

= 10 x 99

= 990

Cảm ơn bạn.

=432,5x100=43250

432,5 x 36 + 432,5 x 39 + 432,5 x 26 – 432,5

= 432,5 x 36 + 432,5 x 39 + 432,5 x 26 – 432,5 x 1

= 432,5 x  ( 36 + 39 +26+1)

= 432,5 x 100 = 43250

 60x [7/12+4/15]

60x153/180

=9180/180

b 1/2x2/3x3/4x4/5x5/6x6/7x7/8x8/9=40320/4032