My family have 4 people. There are my mother,my father,my elder sister and me.My parents are both the same age, 50 years old.My father is a teacher ,he is very kind and hard-working. My morther is a nurse, she is interesting, I think she is the most funny person in my family. My elder sister is 18 years old, she is a student and she is very pretty,she not only learns well but also plays the piano very well, I think she will become a pianist in the future. And me, I’m 16 years old and I’m a pupil, in the future i'll be a marketing staff. I love my familly very much.For me, family always is the assured a reliable support.

Hello every body ! My name is Duy . I am 14 years old . There are 5  people in my family : My father ; my mother ; my older sisters and me . My father is a doctor . He works a hospital in the city center . Every day , he go to work by bus . My mother is a teacher . She learns English at a school near my house . She walks to school every day . I have 2 elder sister . The oldest is a secretary in a company . The younger is a studente . She is learning at Hanoi university . I love my family so much . I feel very happy to be alive in this family.

                                                   My Family :

 As you know , all of us have a faimly.The family is the place we are brought up and look after everyday. Today , I would like to introduce my topic is " My Family"

 I come from a family of 4 people : my parents , my younger brother and me.

 My father is an engineer. He likes reading new spaper and watching TV.He teaches me many helpfull things in the life : know how to love everyone , how to behave well , how to keep clothes and schoolthings clean and tidy , ect .....But sometimes when I make mistakes , he is very strict but frankly my father is so kind and friendly.

 And my mother is a teacher.She is a good woman. She is very carefull.My mother cooks very well.My brother and I like eatiing her dishes very much especially fried chicken , and so on... My parents love me and my younger brother so much but they don't say.

 And my brother is a good student at Nguyen Ngoc Binh Primary School.He is a active boy in many activities as well as studying. When my brother and I have free time, we often play many many sports and games such as : badminton , volleyball , hide - and - seek , ect....

 And my name is Nhi. I'm a student at class 6/1 at Tran Phu Secondary School. I'm very good at English.

 When all the members in my family have free time , we usually talk about studying as well as working together.Also , I can have meats with my family.I'm so happy and really fun so much. At the weekend , we visit many places such as : park , zoo , beach , ....  I love all the people in my family.

 So being a member of my family , I will try my best to study well to become a good daughter . And my parents will be proud about me.

A=100+(98-97)-(96-95)-(2-1)

A=100+1-1-1

A=97

A = 100 + 98 + 96 + ... + 2 - 97 - 95 - ... - 1

A = 100 + (98 - 97) + (96 - 95) + ... + (2 - 1)

A = 100 + 1 + 1 + ... + 1 (49 số 1)

A = 100 + 49 = 149

A = 100 + 98 + 96 + . . . + 2 − 97 − 95 − . . .1

A = 100 + ( 98 − 97 ) + ( 96 − 95 ) + . . . ( 2 − 1 )

A = 100 + 1 + 1 + 1 + . . . + 1 

A = 100 + 1.49

A = 100 + 49

A=149 

A=(100+...+2)-(97+95+...+1)

100+...+2= (100+2)*((100-2):2+1) :2=2550

97+95+...+1= (97+1)*((97-1):2+1):2=2401

=> A=2550+2401=4951

\(=100+98+96+..+4+2-97-95-..-3-1\)

\(=\left(100+98+96+...+4+2\right)-\left(97+95+..+3+1\right)\)

\(=\left\{\left(100+2\right).50:2\right\}-\left\{\left(97+1\right).49:2\right\}\)

\(=\)       \(2550\)                   \(-\)        \(2401\)

\(=\)                      \(149\)

CHÚC CÁC BẠN HỌC GIỎI

100 - 99 + 98 - 97 + 96 - 95 + ... + 2 - 1

= (100 - 99) + (98 - 97) + (96 - 95) + ... + (2 - 1)

= 1+1+1+1+...+1+1 ( có 50 cặp số 1 ) 

= 1 x 50

=50

100 + 98 + 96 + ... + 2 - 97 - 95 - ... - 1

= 100 + (98 - 97) + (96 - 95) + ... + (2 - 1)

= 100 + 1 + 1 + 1 +...+ 1 ( có 49 số 1 )

= 100 + 1 x 49

= 100 + 49

= 149 

A=100-98+...+4-2(100 -98 =2 là 1 cặp => A có 25 cặp)
=25 . 2 =50
b ( mk hok bt lm )
C=1+2-3-4+5+6-7-8+...-95-96+97+98( 1+2-3-4 là 1 cặp => có 24 cặp dưa 97 và 98)
= (24 . -4) + 97 + 98 =-96 + 97 + 98 =99
T I C K mk nha!!

ket qua =50

A=100-98+...+4-2(100 -98 =2 là 1 cặp => A có 25 cặp)
=25 . 2 =50
b ( mk hok bt lm )
C=1+2-3-4+5+6-7-8+...-95-96+97+98( 1+2-3-4 là 1 cặp => có 24 cặp dưa 97 và 98)
= (24 . -4) + 97 + 98 =-96 + 97 + 98 =99

D=(2-1)+(4-3)+....+(100-99)

D=1+1+1+...+1 ( 50 CẶP)

D=1x50

D=50

= 100+ 98 + 96+....+ 2- ( 1+ 3+...+ 95+ 97+ 99)

= (100+2) x 50: 2- ( 99+1) x 50 :2

= 102 x 25 - 100 x 25

= 25 x (102- 100)

= 25 x 2

=50

D = ( 2 - 1 ) + ( 4 - 3 ) + ... + ( 100 - 99 )

D = 1 + 1 + 1 + ... + 1 ( 50 cặp )

D = 1 x 50

D = 50

La day:

100+(98-97)+(96-95)+(94-93)+...+(52-51)...

=100+1+1+1+...+1

=100+49

=149

=100 + (98 - 97) + (96 - 95) +.......+(2-1)

=100 + 49

=150 

1+ 3-2 + 5-4 + 7-6 + ... + 99-98 - 100 = 
1 + (1 + 1 + 1 + 1 + 1 + ... + 1) - 100 =................(trong ngoặc có 49 số 1 vì 49 x 2 + 1 =99) 
= 1 + 49 - 100 = âm 50. 
Hoặc có cách này: 
1 + 3 + 5 + ... + 97 + 99 - (2 + 4 + 6 + ... + 100) = - 50.

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