19/20x2/100+19/20x2/100

= [19/20+19/20]x2/100

= 38/20x2/100

= 19/500

75/76x102/100-75/76x2/100

= [102/100-2/100]x75/76

= 1x75/76

= 75/76

3x7/10+7/10x5+2x7/10

= [3+5+2]x7/10

= 10x7/10

= 7

giá trị biểu thức 

2/5+2/3x3/4

= 2/5+1/6

= 17/30

1/2x1/3-1/8

= 1/6-1/8

= 1/24

[1/2+1/3]:3/9

= 5/6:3/9

= 5/2

                       nhớ tick cho tớ nhé

rùi đó

a: \(2\dfrac{2}{10}=2,2\)

\(4\dfrac{31}{100}=4,31\)

9/10=0,9

51/10=5,1

75/100=0,75

125/100=1,25

1075/1000=1,075

\(14\dfrac{17}{100}=14,17\)

b: 1/2=0,5

3/4=0,75

4/5=0,8

5/8=0,625

\(2\dfrac{1}{2}=2,5\)

\(3\dfrac{1}{4}=3,25\)

\(1\dfrac{3}{5}=1,6\)

\(4\dfrac{3}{8}=4,375\)

\(\dfrac{1}{4}-\dfrac{3}{5}-\dfrac{75}{100}=\dfrac{1}{4}-\dfrac{3}{5}-\dfrac{15}{20}=\dfrac{5-12-15}{20}=\dfrac{-22}{20}=\dfrac{-11}{10}\)

a) 1 phần 2 = 5 phần 100 = 5 %

b) 3 phần 5 = 6 phần 100 = 6 %

a,Ta có:\(\frac{1}{2}=\frac{1\times50}{2\times50}=\frac{50}{100}=50\%\)

b,\(\frac{3}{5}=\frac{3\times20}{5\times20}=\frac{60}{100}=60\%\)

Vậy...........

1a

75/100+18/21+19/32+1/4+3/21+13/32

= 3/4 +6/7+19/32+1/4+1/7+13/32

= (3/4+1/4)+(19/32+13/32)+(6/7+1/7)

= 1+1+1=3

1b

22/5+51/9+11/4+3/5+1/3+1/4

=22/5+17/3+11/4+3/5+1/3+1/4

=(22/5+3/5)+(17/3+1/3)+(11/4+1/4)

=25/5+18/3+12/4

=5+6+3

=14

toi khong 

a) (38 - 60) + (20 - 38)

= 38 - 60 + 20 - 38

= (38 - 38) + (-60 + 20)

= 0 - 40

= -40

b) 75 - (20 + 75)

= 75 - 20 - 75

= (75 - 75) - 20

= 0 - 20

= -20

c) 32 + (60 - 32)

= 32 + 60 - 32

= (32 - 32) + 60

= 0 + 60

= 60

d) (81 - 36) - (81 - 36)

= 81 - 36 - 81 + 36

= (81 - 81) + (-36 + 36)

= 0 + 0

= 0

e) (2 + 4 + 6 + 8) - (1 + 3 + 5 + 7)

= 2 + 4 + 6 + 8 - 1 - 3 - 5 - 7

= (2 - 1) + (4 - 3) + (6 - 5) + (8 - 7)

= 1 + 1 + 1 + 1

= 4

f) (1 + 3 + 5 + 7 + ... + 99) - (2 + 4 + 6 + 8 + ... + 100)

= 1 + 3 + 5 + 7 + ... + 99 - 2 - 4 - 6 - 8 - ... - 100

= (1 - 2) + (3 - 4) + (5 - 6) + (7 - 8) + ... + (99 - 100)

= -1 - 1 - 1 - 1 - ... - 1 (50 chữ số 1)

= -50

giúp mình với huhuhuhuhuhu

cảm ơn bạn nhiều !!!!!!!!!✿❤☺

\(a)5\frac{3}{5}+1\frac{3}{4}+4\frac{1}{4}+3\frac{2}{5}\)

\(=\)\((5\frac{3}{5}+3\frac{2}{5})+(1\frac{3}{4}+4\frac{1}{4})\)

\(=[8+(\frac{3}{5}+\frac{2}{5})]+[5+(\frac{3}{4}+\frac{1}{4})]\)

\(=(8+1)+(5+1)\)

\(=9+6=15\)

\(b)\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)

\(=\frac{3}{4}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)

\(=(\frac{3}{4}+\frac{1}{4})+(\frac{18}{21}+\frac{3}{21})+(\frac{19}{32}+\frac{13}{32})\)

\(=1+1+1=3\)

_Học tốt_