=1/387/32=387/32

Lời giải:
$1+2+3+....+25$

$=(1+25)+(2+24)+(3+23)+(4+22)+(5+21)+(6+20)+(7+19)+(8+18)+(9+17)+(10+16)+(11+15)+(12+14)+13$

$=\underbrace{26+26+26+...+26}_{12}+13$

$=26\times 12+13=325$

a,= ( 1/14 + 13/14 ) + ( 4/11 + 14/22 )

   =         1               +             1

   =  2

b, = ( 2/26 + 12/13 ) + (3/4 + 25/100 ) + ( 4/7 + 9/21)

    =      1                  +            1             +         1

    =   3

thanks !!!

7 x 9 x 36 + 63 x 64

= 63 x 36 + 63 x 64

= 63 x ( 36 + 64 )

= 63 x 100

= 6300

HT và $$$

Tính bằng cách thuận tiện nhất 27*36/9 nhanh lên nhé đang vội

TL:

4dm²32cm²= 72cm²

6000cm²= 60dm²

Học tốt 👍

a] 72 cm2  

\(\dfrac{12}{6}+\dfrac{15}{7}=2+\dfrac{15}{7}=\dfrac{14}{7}+\dfrac{15}{7}=\dfrac{29}{7}\\ \dfrac{12}{13}-\dfrac{8}{9}=\dfrac{108}{117}-\dfrac{104}{117}=\dfrac{4}{117}\\ \dfrac{43}{54}+\dfrac{76}{8}=\dfrac{43}{54}+\dfrac{19}{2}=\dfrac{43}{54}+\dfrac{513}{54}=\dfrac{556}{54}=\dfrac{278}{27}\)

\(\dfrac{12}{6}+\dfrac{15}{7}=\dfrac{84}{42}+\dfrac{90}{42}=\dfrac{174}{42}=\dfrac{29}{7}\)

\(\dfrac{12}{13}-\dfrac{8}{9}=\dfrac{108}{117}-\dfrac{104}{117}=\dfrac{4}{117}\)

\(\dfrac{43}{54}+\dfrac{76}{8}=\dfrac{344}{432}+\dfrac{4104}{432}=\dfrac{4448}{432}=\dfrac{278}{27}\)

Lôi máy tính ra 

=(11-12)+(13-14)+(15-16)+(17-18)+(19-20)+21+20

=-1+-1+-1+-1+-1+41

=36            

1,8,27,64,125,216,343. nhớ k

a.1872

b.3676

2 tui cũng là army yiu bts nhìu 

----jung hosoek---

a) 12 x 13 + 12 x 49 + 12 x 14 +14 x 78 = 1873

b) 34 x 34 + 56 x 45 = 3676