Tìm y :
102,5 : ( y - 69,3 ) = 5
Tính giá trị biểu thức
a) 365,4 : ( 25,2 + 18,3 ) - ( 40 - 32,3 ) ✖ 0,2
b) \(\dfrac{2}{5}\): ( \(\dfrac{4}{5}\) - \(\dfrac{1}{2}\) ) + \(\dfrac{3}{4}\)
\(\dfrac{3}{4}\) x 36 + 75% x 23 + \(\dfrac{75}{100}\) + 0,75 x 40
= ..... x 36 + ....... x 23 + ..... + 0,75 x 40
= ..... x ( 36 + 23 + 1 + ..... )
= ..... x 100
= .....
Bài 1:
\(a,\dfrac{1}{5}+\dfrac{1}{10}+\dfrac{1}{20}+\dfrac{1}{40}+...............+\dfrac{1}{1280}\)
\(b,\dfrac{1}{3}+\dfrac{1}{9}+\dfrac{1}{27}+\dfrac{1}{81}+..............+\dfrac{1}{59049}\)
\(c,\dfrac{1}{2}\times3+\dfrac{1}{3}\times4+\dfrac{1}{4}\times5+\dfrac{1}{5}\times6\)
a, x.2 + x.5 = 14 b, x.9 + x = 20
c, x: \(\dfrac{3}{2}\) + x.\(\dfrac{1}{3}\) = 1999 d,11.(x+2) = 5.x + 40
e, 11.(x-6) = 4.x + 11 f, (3.x - 4) : x + 10 = 12
g, (5.x + 7) : x + 20 = 26 h, x.1999 - x = 1999.1997 + 1999
***dấu chấm(.) = dấu nhân(x)***
a, x.2 + x .5 = 14 b, x.9 + x = 20
c, x: \(\dfrac{3}{2}\) + x. \(\dfrac{1}{3}\) = 1999 d, 11.(x+2) = 5.x + 40
e, 11.(x-6) = 4.x + 11 f, (3.x - 4) : x + 10 = 12
g, (5.x + 7) : x + 20 = 26 h, x.1999 - x = 1999.1997 + 1999
\(\dfrac{1}{3}\) + \(\dfrac{1}{15}\) + \(\dfrac{1}{40}\) + ... + \(\dfrac{1}{101,103}\)
500+40+\(\dfrac{5}{10}\) +\(\dfrac{3}{1000}\) =?
Tính rồi viết kết quả dưới dạng số thập phân:
a) \(\dfrac{1}{10}\) + \(\dfrac{4}{20}\) + \(\dfrac{9}{30}\) + \(\dfrac{16}{40}\) + \(\dfrac{25}{50}\) + \(\dfrac{36}{60}\) + \(\dfrac{49}{70}\) + \(\dfrac{64}{80}\) + \(\dfrac{81}{90}\)
b) ( \(\dfrac{4}{5}\) x \(\dfrac{3}{8}\) + \(\dfrac{4}{5}\) x \(\dfrac{5}{8}\) - \(\dfrac{4}{5}\) x \(\dfrac{7}{8}\) ) : \(\dfrac{1}{2}\)
tính nhanh
\(\dfrac{1}{3}\) + \(\dfrac{1}{7}\) +\(\dfrac{1}{5}\) +\(\dfrac{32}{40}\) +\(\dfrac{48}{56}\) +\(\dfrac{14}{21}\)
giúp mình với nhé
\(\dfrac{3}{40}\)m = ? dm