C1: 1452 : 3 - 1452 : 2 

= 484 - 726 = - 242

C2: 1452 : 3 - 1452 : 2

= 1452 x \(\frac{1}{3}-1452\)x \(\frac{1}{2}\)

= 1452 x \(\left(\frac{1}{3}-\frac{1}{2}\right)\)

= 1542 x \(\frac{-1}{6}\)= -242

Chúc bạn học tốt ! Nếu đúng thì k mik vs nha!!!

a) 41/45

b) BC(79,52)= 4108

a) = 41/45

b) bc (79;52) = 4108

k nha

1: =7/2+23/5=35/10+46/10=81/10

2: =6/8+53/8=59/8

3: =43/8+65/7=821/56

\(a,3\dfrac{1}{2}+4\dfrac{3}{5}=\dfrac{81}{10}\\ b,\dfrac{3}{4}+6\dfrac{5}{8}=\dfrac{59}{8}\\ 5\dfrac{3}{8}+9\dfrac{2}{7}=\dfrac{821}{56}\\ 4,4\dfrac{1}{2}-2\dfrac{3}{10}=\dfrac{11}{5}\)

a=15+15=30

b=756:1-0=756

c=1-1+10-10=0

A = ( 15 : x + 15 * x ) + 2009 * y

= 30 * x + 2009 * y

Thay x = 1 và y = 0 vào A ta có :

A = 30 x 1 + 2009 x 0

= 30 + 2009 

= 2039

B = y : ( 119 * x + 4512 ) + ( 756 : x - y )

Thay x = 1 và y = 0 vào B ta có :

B = 0 : ( 119 x 1 + 4512 ) + ( 756 : 1 - 0 )

= 0 + 756 

= 756

 C = ( 10 + y ) : ( 10 - y ) - x + 10 * x - 10 : x + y

Thay x = 1 và y = 0 vào C ta có :

C = ( 10 + 0 ) : ( 10 - 0 ) - 1 + 10 x 1 - 10 : 1 + 0

= 10 : 10 - 1 + 10 - 10

 = 1 - 1 + 10 - 10

= 0

2. Tính (+5) + ( +4) = 9

3.Tính (- 9) + ( - 1) = -10

4.Tính : 28 + (-15) = 13

5.Tính (-15) + 12 = - 3

6.Tính (-25) + 25 = 0

7.Tính : 13 - 17 = - 4

8.Tính : (-78) - 9 = - 87

9.Tính : ( -24) - ( - 16) = - 8

10.Tính : 17 - (-3) = 20

11.Tính nhanh : (-21) - ( 48 + 52 - 21) = -100

2,  (+5)+(+4)=+9 hoạc 9 cũng được

3,  (-9)+(-1)=-10

4,  28+(-15)=13

5,  (-15)+12=-3

6,  (-25)+25=0

7,  13-17=4

8,   (-78)-9=-87

9,  (-24)-(-16)=-40

10, 17-(-3)=20

11,  (-21+21)-(48-52)=-4

a: \(\frac{52}{17}>\frac{51}{17}=3\)

\(3=\frac{121}{41}>\frac{120}{41}\)

Do đó: \(\frac{52}{17}>\frac{120}{41}\)

b: \(\frac34+\frac14:\left(\frac{7}{12}-\frac16\right)\)

\(=\frac34+\frac14:\left(\frac{7}{12}-\frac{2}{12}\right)\)

\(=\frac34+\frac14:\frac{5}{12}\)

\(=\frac34+\frac14\times\frac{12}{5}=\frac34+\frac35=\frac{15}{20}+\frac{12}{20}=\frac{27}{20}\)

c: \(372,463\cdot998+744,926\)

\(=372,463\cdot998+372,463\cdot2\)

\(=372,463\times\left(998+2\right)=372,463\times1000=372463\)

d: Số số hạng trong dãy số 2;4;6;...;100 là:

\(\left(100-2\right):2+1=98:2+1=49+1=50\) (số)

\(2-4+6-8+10-12+\cdots+98-100+102\)

\(=\left(2-4\right)+\left(6-8\right)+\cdots+\left(98-100\right)+102\)

=(-2)+(-2)+...+(-2)+102

\(=-2\cdot\frac{50}{2}+102=-50+102=52\)

e: (y+112)-113=79

=>y+112-113=79

=>y-1=79

=>y=79+1=80

f: \(\frac34-y=\frac12\)

=>\(y=\frac34-\frac12=\frac14\)

g: \(\left(\frac45-2\times y\right)+\frac16=\frac56\)

=>\(\frac45-2\times y=\frac56-\frac16=\frac46=\frac23\)

=>\(2\times y=\frac45-\frac23=\frac{12}{15}-\frac{10}{15}=\frac{2}{15}\)

=>\(y=\frac{2}{15}:2=\frac{1}{15}\)

h: (y+1)+(y+2)+...+(y+50)=1750

=>50y+(1+2+...+50)=1750

=>\(50y+50\times\frac{51}{2}=1750\)

=>50y+1275=1750

=>50y=1750-1275=475

=>\(y=\frac{475}{50}=9,5\)

hello bạn lớp mấy vậy???

=(1-2)+(3-4)+...+(51-52)+53

= -1 + -1 + ... + -1 + 53

= -1 x (52:2)+53

= -26 + 53

=27

Làm luôn nhé

\(A=\frac{3}{8}+\frac{1}{5}+\frac{5}{6}>\frac{1}{6}+\frac{5}{6}=1\)

\(A=\frac{3}{8}+\frac{1}{5}+\frac{5}{6}< \frac{3}{8}+\frac{1}{4}+\frac{5}{4}=\frac{3}{8}+\frac{2}{8}+\frac{10}{8}=\frac{15}{8}< \frac{16}{8}=2\)

Vậy 1<A<2

\(B=\frac{5}{11}+\frac{5}{12}+\frac{5}{13}+\frac{5}{14}>\frac{5}{14}.4=\frac{10}{7}>1\)

\(B=\frac{5}{11}+\frac{5}{12}+\frac{5}{13}+\frac{5}{14}< \frac{5}{10}.4=2\)

Vậy 1<B<2