=>12/18<3x/18<16/18
=>3x=15
hay x=5
\(\dfrac{12}{18}< \dfrac{3x}{18}< \dfrac{16}{18}\)
\(3x=\left(13,14,15\right)\)
\(x=\left(\dfrac{13}{3},\dfrac{14}{3},5\right)\)
Tích của 25 số sau có tận cùng là chữ số nào
a) 2 x 2 x 2 x ... x 2 x 2
b) 3 x 3 x 3 x ... x 3 x 3
c) 4 x 4 x 4 x ... x 4 x 4
d) 5 x 5 x 5 x ... x 5 x 5
e) 6 x 6 x 6 x ... x 6 x 6
g) 7 x 7 x 7 x...x 7 x 7
h) 8 x 8 x 8 x... x 8 x 8
i) 9 x 9 x 9 x...x 9 x 9
TÍNH NHANH
1/2 x 2/3 x 3/4 x 4/5 x 5/6 x 6/7 x 7/8 x 8/9 9/10
DỄ LẮM CÁC BẠN LÀM ĐC KO
tính:
1 + 3 + 6 + 10 +....+ 45 + 55/ 1 x 10 + 2 x 9 + 3 x 8 +...+ 8 x 3 + 9 x 2 + 10 x 1
1+2+3+4+5+6+7+8+9+.............+99=X+1+2+3+4+5+6+7+8+9+........................+99
Tìm X
Tìm giá trị của 11 x 10 - 10 x 9 + 9 x 8 - 8 x 7 + 7 x 6 - 6 x 5 + 5 x 4 - 4 x 3 + 3 x 2 - 2 x 1.
tinh
a) 3/5 x 7/8 : 10/9
b) 3 2/7 x 2 1/4 : 1 2/5
c) 6/9 + 24/15 + 12/9 + 6/15
d) 3 2/9 - ( 1 5/8 + 1 2/9 )
1 tính
a,( 5/6 + 3/8 ) x 2/7
b,6/7x2/3:5/7
c,8/9+3/4x4/9
1/9 - 9/9 x 12/6 + 9/8 - 2/3 =
6/7 x 8/9 + 7/9 x 2/7 - 18/21 x 1/9 + 7/9 x 3/7
a)\(\dfrac{7}{8}\)x\(\dfrac{3}{13}\)+\(\dfrac{4}{9}\)x\(\dfrac{4}{13}\)
b)\(\dfrac{6}{5}\)+\(\dfrac{7}{3}\)+\(\dfrac{8}{9}\)
c)23: \(\dfrac{5}{14}\)+\(\dfrac{6}{7}\)+\(\dfrac{4}{9}\)
d)\(4\dfrac{1}{4}\)+\(7\dfrac{3}{7}\)-\(2\dfrac{4}{17}\)
e)8-(9\(\dfrac{2}{11}\)+\(\dfrac{8}{33}\))
