Tính nhanh tổng: 1/2+2/8+3/28+4/77+5/176
tính nhanh phân số
1/2+2/8+3/28+4/77+5/176
Tinh bang cach thuan tien nhat:
A = 1/2 + 2/8 + 3/28 + 4/77 + 5/176
\(\frac{1}{2}+\frac{2}{8}+\frac{3}{28}+\frac{4}{77}+\frac{5}{176}\)
Tìm STN x, biết
1) (x + 2) - 2 = 0 2) (x + 3) + 1 = 7
3) (3x - 4) + 4 = 12 4) (5x + 4) - 1 = 13
5) (4x - 8) - 3 = 5 6) 3 + (x - 5) = 7
7) 8 - (2x - 4) = 2 8) 7 + (5x + 2) = 14
9) 5 - (3x - 11) = 1 10) 16 - (8x + 2) = 6
1, Tìm X,..
a,4/5.x/-1=5/4
5/9-1/3x=1/2
3/4x-1/4x+7/2=-5/4
5/8+1/8x=-1/2
giup minh voi a
Thực hiện phép tính:
1,-4/7 + 2/3x -9/14
2,17/13 - ( 4/13 - 11 )
3, 8 2/7 - ( 3 4/9 + 4 2/7 )
5, ( 2/3 - 1 1/2): 4/3 + 1/2
6, -5/13 + 2/5 + -8/13 + 3/5 - 3/7
7, 6/5 x 3/7 + 6/5 : 7/10 + 6/5
giup minh voi :
S1 : 1+(-2)+3+(-4)+...+2001+(-2002)
S2 1+(-2)+(-3)+4+5+(-6)+(-7)+8+9+(-10)+(-11)+12+...+1997+(-1998)+(-1999)+2000
Giup minh voi cac ban
1+2-3-4+5+6-7-8+.....+994-995-996+997+998