a: 7/8>7/10

b: 16/5>16/7

c: 8/7>1

d: 15/11>1

e: 4/9<1<9/4

f: 11/10>1>10/11

đề bài sai sao ý 9/15 mà nếu 9/ 16 thì ko tính thận tiện đc

\(\dfrac{10}{15}\)x\(\dfrac{9}{16}+\dfrac{7}{15}\)x\(\dfrac{10}{15}\)

=> \(\dfrac{10}{15}\)x\(\left(\dfrac{9}{16}+\dfrac{7}{15}\right)\)

=> \(\dfrac{10}{15}\)x\(\dfrac{247}{240}\)

=> \(\dfrac{247}{360}\)

\(A=\frac{1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}}{1-\frac{1}{2}+\frac{1}{4}-\frac{1}{8}+\frac{1}{16}}\)

Đặt tử số là B, mẫu số là C

\(B=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\)

\(2B=2+1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}\)

\(2B-B=\left(2+1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}\right)-\left(1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\right)\)

\(B=2-\frac{1}{16}\)

\(B=\frac{32}{16}-\frac{1}{16}=\frac{31}{16}\)

\(C=1-\frac{1}{2}+\frac{1}{4}-\frac{1}{8}+\frac{1}{16}\)

\(2C=2-1+\frac{1}{2}-\frac{1}{4}+\frac{1}{8}\)

\(2C+C=\left(2-1+\frac{1}{2}-\frac{1}{4}+\frac{1}{8}\right)+\left(1-\frac{1}{2}+\frac{1}{4}-\frac{1}{8}+\frac{1}{16}\right)\)

\(3C=2+\frac{1}{16}\)

\(3C=\frac{32}{16}+\frac{1}{16}\)

\(3C=\frac{33}{16}\)

\(C=\frac{33}{16}:3=\frac{11}{16}\)

=> \(A=\frac{B}{C}=\frac{31}{16}:\frac{11}{16}=\frac{31}{16}.\frac{16}{11}=\frac{31}{11}\)

TL :

a, ( -12/16 + 7/14 ) - ( 1/13 - 3/13 )

= ( -3/4 + 1/2 ) - (-2/13)

= (-3/4 + 2/4 ) - ( -2/13 )

= -1/4 - ( -2/13 )

= (-13/52 ) - (-8/52)

= -5/52

b, 10/11 + 4/11 : 4 - 1/8 = 10/11 + 1/11 - 1/8

= 11/11 - 1/8

= 1 -1/8 

= 8/8 - 1/8

= 7/8

HT

7/8 

HTTTTTTTTTTTTTTTTTTT

\(=\frac{2^{14}.2^8}{3.2^{15}-2^8-5.2^2.2^{20}}=\frac{2^{22}}{3.2^{15}-2^8-5.2^{22}}=\frac{2^{22}}{2^{22}.\left(3.2^{-7}-2^{-14}-5\right)}=\frac{1}{3.2^{-7}-2^{-14}-5}\)

\(\frac{4^7\times2^8}{3\times2^{15}-16^2-5\times2^2\times\left(2^{10}\right)^2}=\frac{\left(2^2\right)^7\times2^8}{3\times2^{15}-\left(2^4\right)^2-5\times2^2\times2^{20}}=\frac{2^{14}\times2^8}{3\times2^{15}-2^8-5\times2^{22}}=\frac{2^{14}\times2^8}{2^8\times\left(3\times2^7-1-2^{14}\times5\right)}\)

nhóm các số có 2 chữ số với số đuôi tương tự.VD:(11-1)+(12-2)...

Chúc bạn làm đc

Bài làm:

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 ) { có 8 nhóm } 

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

= ( -1 ) . 8

= 1 ( vì các số âm là số chẵn )

Đây là bài làm của mình, mình tính theo cách tính nhanh nha

KO HIỂU ?????

`Answer:`

\(-\frac{7}{8}:\frac{21}{16}-\frac{5}{3}.\left(\frac{1}{5}-\frac{7}{10}\right)\)

\(=-\frac{7}{8}.\frac{16}{21}-\frac{5}{3}.\left(-\frac{1}{2}\right)\)

\(=-\frac{2}{3}-\left(-\frac{5}{6}\right)\)

\(=\frac{1}{6}\)

\(\frac{1}{5}.\left(\frac{1}{2}-\frac{1}{3}\right):\left(-\frac{9}{10}\right)+\left(-\frac{7}{3}\right)\)

\(=\frac{1}{5}.\frac{1}{6}.\left(-\frac{10}{9}\right)-\frac{7}{3}\)

\(=\frac{1}{30}.\left(-\frac{10}{9}\right)-\frac{7}{3}\)

\(=-\frac{1}{27}-\frac{7}{3}\)

\(=-\frac{64}{27}\)