1 are

2 Does - walk

3 is - are learning

4 are - doing

5 Does - walk

6 don't play

7 Is - working

8 is doing

9 are playing

10 is - living

11 teaches - is teaching

12 is studying

119.Phong, An , Ha, Lan (be)__________are______________.close friend.

120.______does_____your mother(walk)___walk______to market?

121.It (be)______is____10.00.We (learn)________are learning___________our lesson.

122.What____are_______you (do)______doing______now?

123._____Does_____your mother (walk) walk to work every day?

124.They (not play)________don't play________soccer in the morning.

125.___Is_________Hai(work)______working______in the garden at the moment?

126.My brother (do)___________is doing___________his homework in his room now .He do it every day.

127.James and his brother (play )_______are playing___________soccer at the moment.They (play) _____play____________it every afternoon.

128.Where______is__________the old man (live)____living_______now?

129.Mr.Smith often (teach)_________teaches______class 4A,but this morning he (teach) ________is teaching__________class 4B.

130.It’s 7.30 now. She (study)_________is studying______ science in the classroom.

127

                  127                 

Tìm x

a) X x 15 + X x 13 = 560 x 45

( X + X x 2 ) : 34 = 504

360 : X - 126 = X = 6

58 x X - 934 = 6722

14968 - X x 5 = 4968

b) X x 125 - X x 73 = 1196

246 : X = 34 : X = 5

2005 + X x 34 = 5337

X : 1234 = 127 ( dư 360 )

Đáp án cần chọn là: D

M = 1 + 1 2 + 1 2 2 + 1 2 3 + ... + 1 2 99 + 2 2 100 2 M = 2. 1 + 1 2 + 1 2 2 + 1 2 3 + ... + 1 2 99 + 2 2 100 = 2 + 1 + 1 2 + 1 2 2 + 1 2 3 + ... + 1 2 99

Ta có : 

M = 2 M − M = ( 2 + 1 + 1 2 + 1 2 2 + 1 2 3 + ... + 1 2 99 ) − ( 1 + 1 2 + 1 2 2 + 1 2 3 + ... + 1 2 99 + 2 2 100 ) M = 2 M − M = 2 + 1 + 1 2 + 1 2 2 + 1 2 3 + ... + 1 2 98 + 1 2 99 − 1 + 1 2 + 1 2 2 + 1 2 3 + ... + 1 2 99 + 1 2 100 = 2 − 1 2 100 = 2 101 − 1 2 100

Ta có 

Nên 

Do đó 2S - S = 

a,x-235=445

x= 445 + 235

x = 680

vậy x= 680

b, 546 - (x - 123) = 239

x-123= 546 - 239

x-123 = 307

x=307+ 123

x= 430

vậy x= 430

c, 5. (x-17)+ 12= 122

5.(x-17)= 122 -12

5.(x-17) = 110

x-17= 110: 5

x-17= 22

x= 22+ 17

x= 39

Vậy x= 39

Bài 2.Tìm số tự nhiên x biết:

a,x-235=445

          x=445+235

          x=680

Vậy x=680

b,546-(x-123)=239

   x-123=546-239

   x-123=307

          x=307+123

          x=430

c,5.(x-17)+12=122

   5(x-17)=122-12

   5(x-17)=110

    x-17=110:5

     x-17=22

         x=22+17

         x=39

a, x=445+235

       x=680

b, x-123=546-239

x-123=307

x=307+123=430

c là 5 phẩy bao nhiêu vậy bạn???

dề bài?

40 x 123 x 250 - 50 x 122 x 20

=(250x40)x123-122x(50x20)

=10000x123-122x100

=1230000-12200

=1217800

alo

\(\dfrac{x+1}{124}+1+\dfrac{x+2}{123}+1=\dfrac{x+3}{122}+1+\dfrac{x+4}{121}+1\)

\(\Leftrightarrow\dfrac{x+125}{124}+\dfrac{x+125}{123}=\dfrac{x+125}{122}+\dfrac{x+125}{121}\)

\(\Leftrightarrow\left(x+125\right)\left(\dfrac{1}{124}+\dfrac{1}{123}-\dfrac{1}{122}-\dfrac{1}{121}\ne0\right)=0\Leftrightarrow x=-125\)

<=>\(\dfrac{x+1}{124}+\dfrac{x+2}{123}-\dfrac{x+3}{122}-\dfrac{x+4}{121}=0\)

<=>\(\left(\dfrac{x+1}{124}+1\right)+\left(\dfrac{x+2}{123}+1\right)-\left(\dfrac{x+3}{122}+1\right)-\left(\dfrac{x+4}{121}+1\right)=0\)

<=>\(\dfrac{x+125}{124}+\dfrac{x+125}{123}-\dfrac{x+125}{122}-\dfrac{x+125}{121}=0\)

<=>\(\left(x+125\right)\left(\dfrac{1}{124}+\dfrac{1}{123}-\dfrac{1}{122}-\dfrac{1}{121}\right)=0\)

<=>x+125=0

<=>x=-125