\(\dfrac{63\times81}{135\times84}\text{=}\dfrac{3\times3\times7\times3\times3\times3\times3}{3\times3\times3\times5\times2\times2\times3\times7}\text{=}\dfrac{9}{20}\)

35354fw

\(\dfrac{9.7.9.3.3}{9.3.5.7.4.3.2}=\dfrac{9}{20}\)

63x81/135x84=3x3x7x3x3x3x3/3x3x3x5x22x2x7=9/20

1111x5/1515x7=101x11x5/101x3x5x7=11/21

Hoặc 1111x5/1515x7=1111x5/303x5x7=1111/303x7=1111/2121=1111:101/2121:101=11/21

\(\dfrac{4.4.2.5.5.2}{5.5.4.4.2}=2\)

a: \(=\dfrac{32}{48}\cdot\dfrac{50}{75}=\dfrac{2}{3}\cdot\dfrac{2}{3}=\dfrac{4}{9}\)

b: \(=\dfrac{7\cdot9\cdot81}{27\cdot5\cdot84}=\dfrac{9\cdot81}{27\cdot3}\cdot\dfrac{7}{5\cdot28}=9\cdot\dfrac{1}{4\cdot5}=\dfrac{9}{20}\)

\(a,\dfrac{8\times4\times50}{48\times75}=\dfrac{2\times2\times2\times2\times2\times25}{2\times2\times2\times2\times3\times25\times3}=\dfrac{2\times2}{3\times3}=\dfrac{4}{9}\)

\(b,\dfrac{7\times9\times81}{9\times3\times5\times84}=\dfrac{7\times9\times9\times3\times3}{9\times3\times5\times7\times3\times4}=\dfrac{9}{5\times4}=\dfrac{9}{20}\)

b,7×9×819×3×5×84=7×9×9×3×39×3×5×7×3×4=95×4=920

để chị giải đã nhé .., đợi chị xíu nha( lớp 5)

a: 1792, 3600

b:5103

c:11340

em nhé 

 ~chúc em học tốt ~     <3

mình lớp 4 

a) = (50-1)^2 = 50^2 - 2.50 + 1 = 2500 - 100 + 1 = 2401

b) = (50+1)^2 = 50^2 + 2.50 + 1 = 2601

c) = 9900

a) \(52^2\)

\(=\left(50+2\right)^2\)

\(=50^2+2\cdot2\cdot50+2^2\)

\(=2500+200+4\)

\(=2704\)

b) \(98^2\)

\(=\left(100-2\right)^2\)

\(=100^2-2\cdot100\cdot2+2^2\)

\(=10000-400+4\)

\(=9604\)

`a, 52^2 = (50+2)^2 = 2500 + 200 + 4 = 2704`

`b, 98^2  = (100-2)^2 = 100^2 - 2 . 100 . 2 + 4 = 10000 - 400 + 4`

`= 9604`

\(a,9\times435\times4+12\times565\times3\)

\(=36\times435+36\times565\)

\(=36\times\left(435+565\right)\)

\(=36\times1000\)

\(=36000\)

\(b,4\times1368\times21-7\times368\times12\)

\(=84\times1368-84\times368\)

\(=84\times\left(1368-368\right)\)

\(=84\times1000\)

\(=84000\)

TL

$a)9\times 435\times 4+12\times 565\times 3$

$=36\times 435+36\times 565$

$=36\times \left(435+565\right)$

$=36\times 1000$

$=36000$

$b)4\times 1368\times 21-7\times 368\times 12$

$=84\times 1368-84\times 368$

$=84\times \left(1368-368\right)$

$=84\times 1000$

$=84000$

$HT$