Question

[Cao Thiên Anh]

Tính nhanh

A) 25 . 189 - 25.88 -25

B) 38.66 - 38.56 + 62.65 - 62.55

C) 29.69 + 29.31- 23.100

D ) ( 519.288-516.288) : 288

Answer 1

[Nguyễn Gia Khánh]

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)

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

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

\(=288\times3\div288\)

\(=3\)

Answer 2

[Hà Anh]

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)

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

$=288\times \left(519-516\right)÷288$

$=288\times 3÷288$

$=3$