C ầ n l à m c á c h r a k h ô ng b ạ n ơ i

a) 1800.5=9000

b) 36.25= 900

c) 36600:50=732

d)220000:5000=44

a) = 9000

b) = 900

c) = 732

d) = 44

25.(187+18+1382)

= 25.(187+1400)

=25.1400+187

=3500 +187

= 35187

a)

     \(25\times189-25\times88-25\)

\(=25\times\left(189-88-1\right)\)

\(=25\times100\)

\(=2500\)

b)

     \(38\times66-38\times56+62\times65-62\times55\)

\(=38\times\left(66-56\right)+62\times\left(65-55\right)\)

\(=38\times10+62\times10\)

\(=10\times\left(38+62\right)\)

\(=10\times100\)

\(=1000\)

c)

    \(29\times69+29\times31-23\times100\)

\(=29\times\left(69+31\right)-23\times100\)

\(=29\times100-23\times100\)

\(=100\times\left(29-23\right)\)

\(=100\times6\)

\(=600\)

d)

    \(\left(519\times288-516\times288\right)\div288\)

\(=288\times\left(519-516\right)\div288\)

\(=288\times3\div288\)

\(=3\)

a)

     $25\times 189-25\times 88-25$

$=25\times \left(189-88-1\right)$

$=25\times 100$

$=2500$

b)

     $38\times 66-38\times 56+62\times 65-62\times 55$

$=38\times \left(66-56\right)+62\times \left(65-55\right)$

$=38\times 10+62\times 10$

$=10\times \left(38+62\right)$

$=10\times 100$

$=1000$

c)

    $29\times 69+29\times 31-23\times 100$

$=29\times \left(69+31\right)-23\times 100$

$=29\times 100-23\times 100$

$=100\times \left(29-23\right)$

$=100\times 6$

$=600$

d)

    $\left(519\times 288-516\times 288\right)÷288$

$=288\times \left(519-516\right)÷288$

$=288\times 3÷288$

$=3$

Trả lời

25.(187+1400)

=25.87+25.1400

=2175+35000

=37175.

25.(187+18+1382)

=25.(187+1400)

=25.187+1400

=25.1400+187

=35000+187

=35187

a) 20 x 4 = 80 

800 x 3 = 2400 

70 x 2 = 140 

6000 x 9 = 54000 

b) 60: 3 = 20 

800 : 8 = 100 

150 : 5 = 30 

6300 : 7 = 900

a, 20 x 4 = 80

800 x 3= 2400

70 x 2 = 140

6 000 x 9 = 54 000

b, 60:3=20

800:8=100

150:5=30

6 300:7 = 900

a) 1012 = (100 + 1)2 = 1002 + 2.100 + 1 = 10000 + 200 + 1 = 10201

b) 1992 = (200 – 1)2 = 2002 – 2.200 + 1 = 40000 – 400 + 1 = 39601

c) 47.53 = (50 – 3)(50 + 3) = 502 – 32 = 2500 – 9 = 2491.

a) 8 000 + 7 000

Nhẩm: 8 nghìn + 7 nghìn = 15 nghìn

Vậy 8 000 + 7 000 = 15 000

16 000 – 9 000

Nhẩm: 16 nghìn – 9 nghìn = 7 nghìn

Vậy 16 000 – 9 000 = 7 000

25 000 + 30 000

Nhẩm: 25 nghìn + 30 nghìn = 55 nghìn

Vậy 25 000 + 30 000 = 55 000

b) 46 000 + 4 000 + 9 000 = 50 000 + 9 000 = 59 000

73 000 – 3 000 – 50 000 = 70 000 – 50 000 = 20 000

32 000 + 5 000 – 17 000 = 37 000 – 17 000 = 20 000

\(a,101^2=101.\left(100+1\right)=10100+101=10201.\\ b,75^2-50.75+25^2\\ =75.\left(75-50\right)+25^2\\ =75.25+25^2\\ =25.\left(75+25\right)\\ =25.100\\ =2500.\)

\(c,103.97\\ =\left(100+3\right).97\\ =9700+291\\ =9991\)

a) \(101^2=101.101=10201\)

b) \(75^2-50.75+25^2\)

\(=75^2-2.25.75+25^2\)

\(=\left(75-25\right)^2=50^2=2500\)

c) \(103.97=\left(100+3\right).\left(100-3\right)\)

\(=100^2-3^2=9991\)

a: \(16.42\cdot0.05=0.821\)

b: \(49.36\cdot0.025=1.234\)

c: \(63.15\cdot0.02=1.263\)

bạn giải đúng rồi nhưng mà tách ra rồi làm nhé

40,8 

1020

2301,3

51500

7318

4570

a)40,8
1020
b)2301,3
851,5
c)7318
4570

a. 4,08 . 10 = 40,8

102 . 10 = 1020

b. 23,013 . 100 = 2301,3

8,515 . 100 = 851,5

c. 7,318 . 1000 = 7318

4,57 . 1000 = 4570