thực hiện phép tính :
\(\dfrac{555}{777}\)+\(\dfrac{303}{505}\)+\(\dfrac{111}{555}\)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(A=\dfrac{1}{7}\left(\dfrac{555}{777}+\dfrac{4444}{12221}+\dfrac{33333}{244442}+\dfrac{11}{30}+\dfrac{13}{30}\right)\)
\(=\dfrac{1}{7}\left(\dfrac{5}{7}+\dfrac{4}{11}+\dfrac{3}{22}+\dfrac{23}{30}\right)\\ =\dfrac{1}{7}\left(\dfrac{5}{7}+\dfrac{1}{2}+\dfrac{23}{30}\right)\\ =\dfrac{1}{7}\cdot\dfrac{208}{105}\\ =\dfrac{208}{735}\)
(111 + 222 + 333 + 444 + 555 + 666 + 777 + 888 + 999)x 2.................999 x 2 x 2 x 2 ?
A.(111 + 222 + 333 + 444 + 555 + 666 + 777 + 888 + 999)x 2 > 999 x 2 x 2 x 2 = 9990 > 7992
B.(111 + 222 + 333 + 444 + 555 + 666 + 777 + 888 + 999)x 2 < 999 x 2 x 2 x 2 = 9990 < 7992
C.(111 + 222 + 333 + 444 + 555 + 666 + 777 + 888 + 999)x 2 = 999 x 2 x 2 x 2 = 9990 = 7992
111 + 333 + 666 + 777 +999 +444 + 555 +222
=(111+999) + (333+777) + (666 + 444) +(555+ 222)
=1110 + 1110+1110 + 777
=1110 * 3 + 777
= 3330+ 777=4107
\(999+888+777+666+555+444+333+222+111\)
\(=\left(999+111\right)+\left(888+222\right)+\left(777+333\right)+\left(666+444\right)+555\)
\(=1110+1110+1110+1110+555\)
\(=\left(1110\times4\right)+555\)
\(=4440+555\)
\(=4995\)
=5/7+3/5+1/5=5/7+4/5=25/35+28/35=53/35