a)2

b)75/37

c)0

d)8/27

e)7/19

f)4

ok

a) \(\frac{2}{9}+\frac{1}{5}+\frac{7}{9}+\frac{4}{5}=\left(\frac{2}{9}+\frac{7}{9}\right)+\left(\frac{1}{5}+\frac{4}{5}\right)= 1+1=2 \)

b) \(\frac{19}{37}+\left(1+\frac{19}{37}\right)=\left(\frac{19}{37}-\frac{19}{37}\right)+1=0+1=1\)

c) \(\frac{9}{8}-\left(\frac{17}{7}-\frac{3}{7}\right)+\frac{7}{8}=\frac{9}{8}+\frac{7}{8}-\left(\frac{17}{7}-\frac{3}{7}\right)=2-2=0\)

d) \(\frac{3}{5}\times\frac{8}{27}\times\frac{5}{3}=\frac{3}{5}\times\frac{5}{3}\times\frac{8}{27}=1\times\frac{8}{27}=\frac{8}{27}\)

e) \(\frac{7}{19}\times\frac{1}{3}+\frac{7}{19}\times\frac{2}{3}=\frac{7}{19}\times\left(\frac{1}{3}+\frac{2}{3}\right)=\frac{7}{19}\times1=\frac{7}{19}\)

f) \(\frac{12}{5}\times4-4\times\frac{7}{5}=4\times\left(\frac{12}{5}-\frac{7}{5}\right)=4\times1=4\)

5

10

15

20

25

30

35

40

45

1+1+1+1+1=...?

2+2+2+2+2=...?

3+3+3+3+3=...?

4+4+4+4+4=4x5=20

5+5+5+5+5=5x5=25

6+6+6+6+6=6x5=30

7+7+7+7+7=7x5=35

8+8+8+8+8=8x5=40

9+9+9+9+9=9x5=45

18 nha

bằng 17 đúng ko 

      k mình đi

Khó quá mk ko bít

7+3=10

4-3=1

7-4=3

trả lời :

7+3=10

3+8=11

5+7=12

10

11

12

30 x 3 = 90

7+7+7x7 = 14 + 49= 63

30x3= 90

7+7+7x7=63

bằng 0 nhé Na 

k cho mk đi

Bằng 0 bn ak 

=21 đó

21 đó bạn

1 + 1 =2

2+2 =4

3+3=6

7+7 =14

1+1=mũi tên

2+2=con cá

3+3=8

7+7=tam giác

tick nha Nẹji