=5*[55+13+32]

=5*100                     [* là dấu nhân]

=500

5x55+13x5+32

=5x(55+13+32)

=5x100

=500

( 1 - 3/4 ) x ( 1 - 3/7 ) x ( 1 - 3/10 ) x ( 1 - 3/13 ) x ......x ( 1 - 3/97 ) x ( 1 - 3/100 ) . 

= 1/4 x 4/7 x 7/10 x ... x 97/100 . 

Khử đi các số giống nhau . 

= 1/100 nha bạn . 

1 − 4 3 1 − 7 3 1 − (10 3 ... 1 − 97 3 1 − 100 3 = 4 1 . 7 4 . 10 7 ..... 97 94 . 100 97 = 4.7.10.....97.100 1.4.7.....94.97 = 100 1 

toán lớp 5 khó thế bạn

5/13 x 11/19 + 11/19 x 21/13

=11/19 x ( 5/13 + 21/13 )

=11/19 x 26/13

=11/19 x 2

=22/19

Sửa đề \(\frac{2018}{2019}\times\frac{9}{13}+\frac{2018}{2019}\times\frac{5}{13}-\frac{2018}{2019}\times\frac{1}{13}\)

Ta có: \(\frac{2018}{2019}\times\frac{9}{13}+\frac{2018}{2019}\times\frac{5}{13}-\frac{2018}{2019}\times\frac{1}{13}\)
\(=\frac{2018}{2019}\times\left(\frac{9}{13}+\frac{5}{13}-\frac{1}{13}\right)\)

\(=\frac{2018}{2019}\times\frac{13}{13}=\frac{2018}{2019}\)

13/19 x 23/11 - 13/19 x 8/11 - 13/19 x 4/11

= 13/19 x (23/11 - 8/11 - 4/11)

= 13/19 x 1

= 13/19

\(\dfrac{13}{19}\times\dfrac{23}{11}-\dfrac{13}{19}\times\dfrac{8}{11}-\dfrac{13}{19}\times\dfrac{4}{11}\\ =\dfrac{13}{19}\times\left(\dfrac{23}{11}-\dfrac{8}{11}-\dfrac{4}{11}\right)\\ =\dfrac{13}{19}\times1=\dfrac{13}{19}\)

36/11 x 22/17 x 51/72

= 36 x 22 x 51/11 x 17 x 72

= 36 x 2 x 11 x 17 x 3/11 x 17 x 36 x 2

= 3

22/16 x 64/55 x 27/13

= 22 x 64 x 27/16 x 55 x 13

=2 x 11 x 16 x 4 x 27/16 x 5 x 11 x 13

= 216/65

36 x 48/12 x 24 + 18 x 104/36 x 4

= 12 x 3 x 2 x 24/12 x 24 + 18 x 13 x 2 x 4/ 18 x 2 x 4

= 6 + 13

= 19

=

bn đó làm sai bài cuối cũng dc k à

tính bằng cách thuận tiện nhất :

100 x 55 + 100 x 45 x 10

= 100 x 55 + 100 x 45 x 10

= 100 x 55 + 100 x 450

= 100 x ( 55 + 450 )

= 100 x 500

= 50000

100x55+100x45x100

=100x(55+45)x10

=100x100x10

=1000x10

=10000

       Các bn k mik nha

\(\dfrac{5}{13}\times\dfrac{7}{11}+\dfrac{5}{13}\times\dfrac{2}{11}+\dfrac{8}{13}\times\dfrac{9}{11}\)

\(=\dfrac{5}{13}\times\left(\dfrac{7}{11}+\dfrac{2}{11}\right)+\dfrac{8}{13}\times\dfrac{9}{11}\)

\(=\dfrac{5}{13}\times\dfrac{9}{11}+\dfrac{8}{13}\times\dfrac{9}{11}\)

\(=\dfrac{9}{11}\times\left(\dfrac{5}{13}+\dfrac{8}{13}\right)\)

\(=\dfrac{9}{11}\times1\)

\(=\dfrac{9}{11}\)

a) \(20,23\times21+20,23\times80-20,23\)

\(=20,23\times\left(21+80-1\right)\)

\(=20,23\times100\)

\(=2023\)

a, =13x(27+2x35+4-1)=13x100=1300

b, =(99-99):(1x2x...x10)=0

tick nha!