ai rảnh mà tính bằng 2 cách

b . 3/7 . 16/33 + 16/33 . 4/7

=   16/33 . ( 3/7 + 4/7 ) 

=    16/33 . 7/7

=     16/33 . 1

=   16/33 

c2    3/7 . 16/33 + 16/33 . 4/7

=      16/77 + 64/231

=     48/231 + 64/231 

=              112/231

=      16/33 

chúc em học giỏi !!! 

a . 5/24 . 5/12 . 24

= ( 5/24 . 24 ) .5/12

=    5 . 5/12

= 25/12 

C2 :           5/24 . 5/12 . 24 

=      5/24 . ( 5/12 . 24 ) 

=      5/24 . 10 

=    50/24

= 25/12 

Trả lời :

Sai 

Số cần tìm là :

\(\frac{5}{6}:\frac{2}{3}=\frac{5}{4}\)

~~Học tốt~~

Nhầm xíu :

Sai

\(\frac{2}{3}\text{ của }\frac{5}{6}\text{ là}:\frac{2}{3}\times\frac{5}{6}=\frac{10}{18}\)

\(\frac{7}{4}\)x(\(\frac{33}{12}\)+\(\frac{33}{20}\)+\(\frac{33}{30}\)+\(\frac{33}{42}\))

=\(\frac{7}{4}\)x\(\frac{44}{7}\)

=\(\frac{308}{28}\)=11

\(\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{12}{15}+\frac{22}{33}+\frac{48}{64}\)

\(=\frac{11}{33}+\frac{16}{64}+\frac{3}{15}+\frac{12}{15}+\frac{22}{33}+\frac{48}{64}\)

\(=\left(\frac{11}{33}+\frac{22}{33}\right)+\left(\frac{16}{64}+\frac{48}{64}\right)+\left(\frac{3}{15}+\frac{12}{15}\right)\)

\(\frac{33}{33}+\frac{64}{64}+\frac{15}{15}\)

\(=1+1+1\)

\(=3\)

ket qua la 3 do

 x + 3/4 = 5/3

 x = 11/12

 x - 1/6 = 5/12

x = 1/4

x+3/4=5/3

x=5/3-3/4

x=11/12

.............

x-1/6=5/12

x=5/12-1/6

x=1/4

HT

4.

Doi 450dag = 4,5kg  35hg = 3,5kg  6000g = 6kg

5 qua dua nang la:

   4,5 + 3,5 + 6 = 14 ( kg )

        Dap so: 14kg

HT~

5.

Than ca nang la:

   10000 - 750 - 450 = 8800 ( g )

      D/S : 8800g

HT~

a)70=2*5*7

=>2*3*5/70=3/7

b)33*4=11*3*2*2=11*6*2

=>2*6*11/33*4=1

c)21*45=9*5*3*7

=>21*45/3*5*7*9=1

\(\frac{2\times3\times5}{70}\)

= \(\frac{2\times3\times5}{7\times2\times5}\)

= \(\frac{3}{7}\)