a)
\(\frac{1.2+2.4+3.6+4.8+5.10}{3.4+6.8+9.12+12.16+15.20}\)
\(\frac{2.3\left(1.2\right)+2.3\left(2.4\right)+2.3\left(3.6\right)+2.3\left(4.8\right)+2.3\left(5.10\right)}{3.4\left(3.4+6.8+9.12+12.16+15.20\right)}\)
\(=\frac{\left(3.4+6.8+9.12+12.16+15.20\right)}{2.3\left(3.4+6.8+9.12+12.16+15.20\right)}=\frac{1}{2.3}=\frac{1}{6}\)

 

 13 - 12 + 11 - 10 - 9 + 8 - 7 - 6 + 5 - 4 + 3 + 2 - 1 
= ( 13 - 12 + 11 - 10 + 8 ) - ( 9 + 1 ) - ( 6 + 4) + ( 3 + 2 + 5 ) - 7 
= 10 - 10 - 10 + 10 - 7 
= ( 10 - 10 ) - ( 10 - 10 ) - 7 
= 0 - 0 - 7 
= - 7

tick minh nha

9 tick nha

 13 - 12 + 11 - 10 - 9 + 8 - 7 - 6 + 5 - 4 + 3 + 2 - 1 
= ( 13 - 12 + 11 - 10 + 8 ) - ( 9 + 1 ) - ( 6 + 4) + ( 3 + 2 + 5 ) - 7 
= 10 - 10 - 10 + 10 - 7 
= ( 10 - 10 ) - ( 10 - 10 ) - 7 
= 0 - 0 - 7 
= - 7

nhóm cứ hai số liên tiếp lại vs nhâu sẽ đk quy luật tổng của toàn số -2

A=2-4+6-8+10-12+14-16+18-20+22-24+26-28+30-32

A= (-2)+(-2)+(-2)+(-2)+(-2)+(-2)+(-2)+(-2)

A= -16

-16

nha!!!!!!!

a, 8*17*125=(8*125)*17=1000*17=17000

b, 4*37*25=(4*25)*37=100*37=3700

1+2-3+4-5+6-7+8-9+10-11+12-13+14-15+16=10

Hok tốt

Nhớ k

#EMNA#

= 1 + (2-3) + (4-5) + (6-7) + (8-9) + (10 - 11) + (12 - 13) + (14 - 15) + 16 

= 1 + (-1) + (-1) + (-1) + (-1) + (-1) + (-1)  + (-1) +16 

= 1 + [(-1) * 7]  + 16 

= 1 + (-7) + 16

= -6 + 16 

= 10 

1+2-3+4-5+6-7+8-9+10-11+12-13+14-15+16

=1+(2-3)+(4-5)+(6-7)+(8-9)+(10-11)+(12-13)+(14-15)+16

=1+(-1)+(-1)+(-1)+(-1)+(-1)+(-1)+(-1)+16

=1+7.(-1)+16=1+(-7)+16=1+9=10

Chúc bạn học tốt

  3x188x8+4x12x6

=3x8x188+4x6x12

=24x188+24x12

=24x(188+12)

=24x 200

=4800

3.188.8+4.12.6

=(3.8).188+(4.6).12

=24.188+24.12

=24.(188+12)

=24.200

=4800

chuc bn hoc gioi!

ai dong y voi y kien cua mk thi !

=4800

=(30+7-37)*(1+2+3+4+5+6+7+8+9+10)

=0*(1+2+3+4+5+6+7+8+9+10)

=0

( 6 x 5  + 7 - 37)x (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 +9 + 10)

0 x 55 = 0

\(\dfrac{10.4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}=\dfrac{5.2.2^{12}.3^{10}+3^9.2^9.2^3.3.5}{2^{12}.3^{12}-2^{11}.3^{11}}\)

\(=\dfrac{5.2^{13}.3^{10}+2^{12}.3^{10}.5}{2^{11}.3^{11}\left(2.3-1\right)}=\dfrac{2^{12}.3^{10}.5\left(2+1\right)}{2^{11}.3^{11}.5}\)

\(=\dfrac{2^{11}.2.3^{10}.5.3}{2^{11}.3^{10}.3.5}=2\)

1+2+3+4+5+6+7+8+9+10+11+12+13-1-2-3-4-5-6-7-8-9-10-11-12

=(1-1)+(2-2)+(3-3)+(4-4)+(5-5)+(6-6)+(7-7)+(8-8)+(9-9)+(10-10)+(11-11)+(12-12)+13

=  0  +  0  +  0  +  0  +   0  +  0  +  0  +  0  +  0  + 0  + 0   +  0  +  13

=                                 13

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 - 1 - 2 - 3 - 4 - 5 - 6 - 7- 8 - 9 - 10 

= (1+12) + (2+11) + (3+10) + ( 4+9) + (5+8) + (6+7) + 13 -  (1+11) - ( 2+10) - ( 3+9) - (4+8) - (5+7) + 6 + 12

= 13 * 7 - 12 * 6 + 6

= 13

Ai k mk mk k lại

= 13 nhé hihi nha