a. -3/4+5.3/13-0,75.36/13
b.4.5/9: (-5/7)+49/9: -5/7
Bài 4: Tính bằng cách thuận tiện
a) 5/9 + 13/7 + 15/13 + 8/7 + 4/9 + 11/13
b) 3/5 + 18/9 + 4/10
a) \(\dfrac{5}{9}+\dfrac{13}{7}+\dfrac{15}{13}+\dfrac{8}{7}+\dfrac{4}{9}+\dfrac{11}{13}\)
\(=\left(\dfrac{5}{9}+\dfrac{4}{9}\right)+\left(\dfrac{13}{7}+\dfrac{8}{7}\right)+\left(\dfrac{15}{13}+\dfrac{11}{13}\right)\)
\(=1+3+2\)
\(=6\)
b) \(\dfrac{3}{5}+\dfrac{18}{9}+\dfrac{4}{10}\)
\(=0,6+2+0,4\)
\(=\left(0,6+0,4\right)+2\)
\(=1+2\)
\(=3\)
\(a\dfrac{5}{9}+\dfrac{4}{9}+\dfrac{13}{7}+\dfrac{8}{7}+\dfrac{15}{13}+\dfrac{11}{13}=\dfrac{9}{9}+\dfrac{21}{7}+\dfrac{26}{13}=1+3+2=6\)
\(b\dfrac{3}{5}+2+\dfrac{2}{5}=\dfrac{5}{5}+2=1+2=3\)
thực hiện phép tính(tính nhanh nếu có thể):
a)2/13 x 5/9+3/13 x 9/11+11/13
b)5/7 x -3/11+-5/7 x 8/11+9/7
Tính
a) ( -3/5+4/9 ):7/11 + (-2/5 +5/9 ) :7/11
b) 4 5/9:(-5/7) +49/9 :(-5/7)
c)6/7 :( 3/26 -3/13 )+ 6/7:(1/10 -8/5)
2 x 6 = .....; 3 x 4 = .....; 4 x 9 = .....; 5 x 8 = .....?
A. 8; 7; 13; 13
B. 12; 12; 36; 40
C. 11; 13; 35; 41
D. 12; 12; 38; 30
a) 92/9 + 13/5 - 56/9
b) 58/7 - (31/9 + 30/7)
c) 2/3 + 1/3 x 9/4 - 13/12
d) 41/8 - 7/4 : 11/5
e) 478/19 : 5/4 - 668/19 : 5/4
f) 32/21 x 49/45 : 16/22 x 15/33
g) 2020x2018+9 / 2019x2020-2011.
Giup minh voi minh dang can gap!!!
58/7 - (31/9 + 30/7)
= 58/7 - 31/9 - 30/7
= (58/7 - 30/7) - 31/9
= 28/7- 31/9
= 4 - 31/9 = 36/9 - 31/9
= 5/9
478/19÷(-5/4)-668/19÷(-5/4)
=(478/19-668/19):(-5/4)
=-10 . (-4/5)
=8
Tính giá trị biểu thức :
A = 6/8 . 8/13 + 6/13 . 9/7 - 3/13 . 6/7
B = ( 5/4 + 3/4 ) . 4/7 . ( 3/4 + 9/4 ) . 4/7
C = -5/7 . 1/35 + 6/49 . ( -8 ) + 16/(-3) . (-3)/8
D = ( 5/10 + 21/28 - 60/72 ) . 24/5
các bạn làm ơn giúp mình với đc ko , mình đang cần gấp !!!!
Trả lời:
\(A=\frac{6}{8}.\frac{8}{13}+\frac{6}{13}.\frac{9}{7}-\frac{3}{13}.\frac{6}{7}\)
\(A=\frac{6}{13}+\frac{54}{91}-\frac{18}{91}\)
\(A=\frac{6}{7}\)
\(B=\left(\frac{5}{4}+\frac{3}{4}\right).\frac{4}{7}.\left(\frac{3}{4}+\frac{9}{4}\right).\frac{4}{7}\)
\(B=\frac{2}{1}.\frac{4}{7}.\frac{3}{1}.\frac{4}{7}\)
\(B=\frac{8}{7}.\frac{12}{7}\)
\(B=\frac{96}{49}\)
a)-3/5.5/7+3/-5.3/7+3/5.-6/7
b)3/13:-11/-6+-3/13:11/-5-2/13
c)1/2.(x+2)+3/8=7/16
d)1/3x+2/5(x+1)=0
-1/3+5/2x=1/6:(-2/9)
a: \(=\dfrac{-3}{5}\cdot\dfrac{5}{7}+\dfrac{-3}{5}\cdot\dfrac{3}{7}+\dfrac{-3}{5}\cdot\dfrac{6}{7}\)
\(=\dfrac{-3}{5}\left(\dfrac{5}{7}+\dfrac{3}{7}+\dfrac{6}{7}\right)=\dfrac{-3}{5}\cdot2=-\dfrac{6}{5}\)
b: \(=\dfrac{3}{13}\cdot\dfrac{6}{11}+\dfrac{3}{13}\cdot\dfrac{5}{11}-\dfrac{2}{13}=\dfrac{3}{13}-\dfrac{2}{13}=\dfrac{1}{13}\)
c: =>1/2x+1+3/8=7/16
=>1/2x=-15/16
=>x=-15/8
d: =>5/2x-1/3=1/6*(-9)/2=-9/12=-3/4
=>5/2x=-3/4+1/3=-9/12+4/12=-5/12
=>x=-1/6
4×7/9×23
2×21/14×15
2×5×13/26×35
9×6-9×3/18
17×5-17/3-20
49+7×49/49
2/3 + 3/4
9/4 + 3/5
5/24 + 1/4
3/15 - 5/35 18/27 - 2/6 37/12 - 3
11/9 x 3/22 7/13 x 13/7 4 x6/7
2/5 : 3/10 3/8 : 9/4 8/21 : 4/7
2/3 + 3/4=17/12
9/4 + 3/5=57/20
5/24 + 1/4=11/24
3/15 - 5/35=2/35 18/27 - 2/6=1/3 37/12 - 3=1/12
11/9 x 3/22=1/6 7/13 x 13/7=1 4 x6/7=24/7
2/5 : 3/10=4/3 3/8 : 9/4=1/6 8/21 : 4/7=2/3
2/3 + 3/4
= 17/12
9/4 + 3/5
= 57/20
5/24 + 1/4
=11/24
3/15 - 5/35
=2/35
18/27 - 2/6
=1/3
37/12 - 3
= 1/12
11/9 x 3/22
=1/6
7/13 x 13/7
=1
4 x6/7
=24/7
2/5 : 3/10
=4/3
3/8 : 9/4
=1/6
8/21 : 4/7
= 2/3
1=17/12
2=57/20
3=11/24
4=2/35 7=1/3 10=1/12
5=1/6 8=1 11=24/7
6=4/3 9=1/6 12=2/3