b) \(\frac{1}{1000}+\frac{13}{1000}+\frac{25}{1000}+...+\frac{87}{1000}+\frac{99}{1000}\)
\(=\frac{1+13+25+...+85+97}{1000}=\frac{\left(97+1\right).\left[\left(97-1\right):12+1\right]:2}{1000}\)
\(=\frac{49.9}{1000}=\frac{441}{1000}.\) ( Đề bài sai nhé bạn tử số : 1; 13; 25; 37; 49 ; 61; 73; 85 ; 97. )
Bài 7 :Tính nhanh:
a) 2/3:5/7x5/7:2/3+1934
b) (30 : 7\(\frac{1}{2}\) +0,5 x 3 -1,5 ) x (4\(\frac{1}{2}\)−\(\frac{9}{2}\)) : ( 14,5 x 1000 )
c) (1999 x 1998 + 1998 x 1997 ) x ( 1 + 1/2 : 1\(\frac{1}{2}\) -1\(\frac{1}{3}\) )
Tính nhanh : B = ( 1999 x 1998 + 1998 x 1997 ) x ( 1 + \(\frac{1}{2}\): 1\(\frac{1}{2}\)- 1\(\frac{1}{3}\))
Mình cần rất gấp
Tính giá trị biểu thức :
B = ( 1999 x 1998 + 1998 x 1997 ) x ( 1 + \(\frac{1}{2}\): 1\(\frac{1}{2}\)- 1\(\frac{1}{3}\))
Tính theo kiểu tính nhanh ý.
( 30: 7 \(\frac{1}{2}\) + 0,5 x 3 - 1,5 ) x (4 \(\frac{1}{2}\) - 9/2) : (14,5 x10)
\(\frac{0,8.0,04.1,25+0,6524+0,3476}{10.125.4.25._{ }8}\)
( 1999 x 1998 x 1998 x 1997 ) x ( 1 + \(\frac{1}{2}\) + 1\(\frac{1}{2}\) + 1\(\frac{1}{3}\))
Bài 1:Tìm x,biết:
a)(1,5*1,9-x-0,5):0,25=7,5:0,125
b)1-\(\left(5\frac{2}{9}+x-7\frac{7}{18}\right)\):2\(\frac{1}{6}\)=0
c)35*\(\left(2\frac{1}{5}-x\right)\)=32
d)\(\frac{4}{3}\)+\(\left(x:2\frac{2}{3}-0,5\right)\)*1\(\frac{35}{55}\)=0,6
e)1\(\frac{1}{3}\)*2\(\frac{2}{4}:\frac{5}{6}\)*1\(\frac{1}{11}\)=11-5:x
Mình cần gấp lắm!Ai nhanh nhất mik tik nha!
\(A=\left(6:\frac{3}{5}-1\frac{1}{6}x\frac{6}{7}\right):\left(4\frac{1}{5}x\frac{10}{11}+5\frac{2}{11}\right)\)\(B=\left(1-\frac{1}{2}\right)x\left(1-\frac{1}{4}\right)x.......x\left(1-\frac{1}{2015}\right)x\left(1-\frac{1}{2016}\right)\)
\(C=5\frac{9}{10}:\frac{3}{2}-\left(2\frac{1}{3}x4\frac{1}{2}-2x2\frac{1}{3}\right):\frac{7}{4}\)
bài 1: tìm x:
a) \(x\cdot\frac{7}{9}=\frac{2}{3}+2\frac{1}{2}\) b) \(\frac{5}{7}+x:\frac{9}{4}=\frac{4}{3}\)
Tính giá trị biểu thức :b,[1999x1998+1998 x 1997 ] x [1+\(\frac{1}{2}\): 1\(\frac{1}{2}\)- 1\(\frac{2}{3}\)]
