1.Biểu thức (-13 + 18 - 27) sau khi bỏ ngoặc là:
13 + 18 - 27
-13 + 18 - 27
-13 - 18 - 27
13 + 18 + 27
Tính nhanh
41/27 × 13/18 -13/18 × 14/27
41/27*13/18-13/18*14/27
41/27* 0 *14/27=
0 *14/27=0
Tinh bang cach thuan tien :
41 / 27 x 13 / 18 - 13 / 18 x 14 / 27
41 / 27 x 13 / 18 - 13 / 18 x 14 / 27 = ( 41 / 27 - 14 / 27 ) x 13 / 18 = 27 / 27 x 13 / 18 = 1 x 13 / 18 = 13 / 18
Cho biểu thức A=1/3+1/4+3/8+2/9+5/12+7/18+1/24+13/36+5/27
Phải bỏ phân số nào để biểu thức A=2
tính giá trị biểu thức
( 15 - 6 13/18 ) : 11 1/27 - 2 1/8 : 1 11/40
tinh giá rị biểu thức
( 15 - 6 13/18 ) : 11 1/27 - 2 1/8 : 1 11/40
7/12+5/18+5/36<x<20/13+44/13+27/13
7/12+5/18+5/36<x<20/13+44/13+27/13
1<x<7
x=2;3;4;5;6
bài 1
a. 5/18 + 8/19 - 7/21 + ( -10/36 + 11/19 + 1/3) - 5/8
b.1/13 + ( -5/18 - 1/13 + 12/17 ) - ( 12/17 - 5/18 + 7/5 )
c.15/14 - (17/23 - 80/87 + 5/4)+(17/23 - 15/14 + 1/4 )
d.1/25 - 4/27 + ( -23/27 + -1/25 - 5/43 ) + 5/43 - 4/7
bài 2
a. x +1/3 = 3/4
b. x - 2/5 = 5/7
c. -x - 2/3 = -6/7
d. 4/7 - x = 1/3
e. x+ 5/2 = -3/2
f. x + 5/6 = -1/12
GIÚP MÌNH VỚI Ạ MÌNH CẢM ƠN TRƯỚC
Bài 1:
a; \(\dfrac{5}{18}\) + \(\dfrac{8}{19}\) - \(\dfrac{7}{21}\) + (- \(\dfrac{10}{36}\) + \(\dfrac{11}{19}\) + \(\dfrac{1}{3}\)) - \(\dfrac{5}{8}\)
= \(\dfrac{5}{18}\) + \(\dfrac{8}{19}\) - \(\dfrac{1}{3}\) -\(\dfrac{10}{36}\) + \(\dfrac{11}{19}\) + \(\dfrac{1}{3}\) - \(\dfrac{5}{8}\)
= (\(\dfrac{5}{18}\) - \(\dfrac{10}{36}\)) + (\(\dfrac{8}{19}\) + \(\dfrac{11}{19}\)) - (\(\dfrac{1}{3}\) - \(\dfrac{1}{3}\)) - \(\dfrac{5}{8}\)
= (\(\dfrac{5}{18}\) - \(\dfrac{5}{18}\)) + \(\dfrac{19}{19}\) - 0 - \(\dfrac{5}{8}\)
= 0 + 1 - \(\dfrac{5}{8}\)
= \(\dfrac{3}{8}\)
b; \(\dfrac{1}{13}\) + (\(\dfrac{-5}{18}\) - \(\dfrac{1}{13}\) + \(\dfrac{12}{17}\)) - (\(\dfrac{12}{17}\) - \(\dfrac{5}{18}\) + \(\dfrac{7}{5}\))
= \(\dfrac{1}{13}\) - \(\dfrac{5}{18}\) - \(\dfrac{1}{13}\) + \(\dfrac{12}{17}\) - \(\dfrac{12}{17}\) + \(\dfrac{5}{18}\) - \(\dfrac{7}{5}\)
= (\(\dfrac{1}{13}\) - \(\dfrac{1}{13}\)) + (\(\dfrac{12}{17}\) - \(\dfrac{12}{17}\)) + (-\(\dfrac{5}{18}\) + \(\dfrac{5}{18}\)) - \(\dfrac{7}{5}\)
= 0 + 0 + 0 - \(\dfrac{7}{5}\)
= - \(\dfrac{7}{5}\)
Bài 1 c;
\(\dfrac{15}{14}\) - (\(\dfrac{17}{23}\) - \(\dfrac{80}{87}\) + \(\dfrac{5}{4}\)) + (\(\dfrac{17}{23}\) - \(\dfrac{15}{14}\) + \(\dfrac{1}{4}\))
= \(\dfrac{15}{14}\) - \(\dfrac{17}{23}\) + \(\dfrac{80}{87}\) - \(\dfrac{5}{4}\) + \(\dfrac{17}{23}\) - \(\dfrac{15}{14}\) + \(\dfrac{1}{4}\)
= (\(\dfrac{15}{14}-\dfrac{15}{14}\)) + (\(-\dfrac{17}{23}+\dfrac{17}{23}\)) - (\(\dfrac{5}{4}\) - \(\dfrac{1}{4}\)) + \(\dfrac{80}{87}\)
= 0 + 0 - 1 + \(\dfrac{80}{87}\)
= - \(\dfrac{7}{87}\)
Bài 1 d;
\(\dfrac{1}{25}\) - \(\dfrac{4}{27}\) + (-\(\dfrac{23}{27}\) + \(\dfrac{-1}{25}\) - \(\dfrac{5}{43}\)) + \(\dfrac{5}{43}\) - \(\dfrac{4}{7}\)
= \(\dfrac{1}{25}\) - \(\dfrac{4}{27}\) - \(\dfrac{23}{27}\) - \(\dfrac{1}{25}\) - \(\dfrac{5}{43}\) + \(\dfrac{5}{43}\) - \(\dfrac{4}{7}\)
= (\(\dfrac{1}{25}\) - \(\dfrac{1}{25}\)) - (\(\dfrac{4}{27}\) + \(\dfrac{23}{27}\)) - (\(\dfrac{5}{43}\) - \(\dfrac{5}{43}\)) - \(\dfrac{4}{7}\)
= 0 - 1 - 0 - \(\dfrac{4}{7}\)
= \(\dfrac{-11}{7}\)
a) Trong các phân số 13/26 ; 14/27 ; 16/28 ; 18/29 ; 20/30 các phân số tối giản là: A. 13/26 ; 16/28 ; 20/30 B. 13/26 ; 14/27 ; 18/29 C. 14/27 D. 14/27 ; 18/29
=>Chọn D. 14/27 ; 18/29
cảm ơn bạn
13 : 4 =
27 : 72 =
18 : 4,8 =
13 : 12,5
13:4=\(\frac{13}{4}\); 27:72=\(\frac{27}{72}=\frac{3}{8}\)
13 :4 = 3,25
27 :72= 0,375
13 : 4,8=2,708(3)
13 : 12,5 =1,04
K TUI NHA