7/9 + 2/3 - 5/18 =
11/5 - 3/4 + 7/15 =
7/8 + 5/9 : 2 =
4/15 : 2/3 + 5/7 =
Bài 1 Tính nhanh
a) -3/7 + 5/13 + 3/7
b) -5/21+-2/21+8/24
c) -5/11+(-6/11+2)
d) (-1/32+1/2)+15/32
e)5/17+ -6/13 + 3/4 + 7/-13+12/17
f) 7/23+-18/18+-4/9+16/23+-5/8
g)1/3+-3/4+3/5+-1/36+1/15+-2/9
h)-1/2+1/3+-1/4+-2/8+4/18+4/9
a)\(-\dfrac{3}{7}+\dfrac{5}{13}+\dfrac{3}{7}\)
=\(\left(-\dfrac{3}{7}+\dfrac{3}{7}\right)+\dfrac{5}{13}\)
=\(0+\dfrac{5}{13}\)
=\(\dfrac{5}{13}\)
1.so sánh
1/2:2/3......2/3:1/2 4/7:2/5......4/7:3/5
4/15:4/7......2/5x10/3 5/6......15/18-11/18
2.viết số thích hợp vào ô trống
2/3=..../18 7/9=49/.... ..../5=18/15
..../3=10/15 5/9=..../45 49/56=7/....
6/8=42/.... 2/9=..../63 49/56=..../8
`1)1/2:2/3 .... 2/3 : 1/2`
`=>1/2xx3/2 .... 2/3xx2`
`=>3/4 .... 4/3`
Vì `3/4 < 1` và `4/3>1`
`=>3/4<4/3`
__
`4/7:2/5 ... 4/7 : 3/5`
`=>4/7xx5/2....4/7xx5/3`
`=>20/14...20/21`
`=>10/7...20/21`
Vì `10/7>1` và `20/21<1`
`=>10/7>20/21`
__
`4/15:4/7....2/5xx10/3`
`=>4/15xx7/4...20/15`
`=>7/15...20/15`
Vì `7<20` nên `7/15<20/15`
__
`5/6...15/18-11/18`
`=>5/6...4/18`
Ta có : MSC : `18`
`5/6 = 15/18`
Vì `15>4` nên `5/6 > 4/18`
`2)2/3=(2xx6)/(3xx6)=12/18`
`7/9=(7xx7)/(9xx7)=49/63`
`6/5=(6xx3)/(5xx3)=18/15`
`2/3=(2xx5)/(3xx5)=10/15`
`5/9=(5xx5)/(9xx5)=25/45`
`49/56=(49:7)/(56:7)=7/8`
`6/8=(6xx7)/(8xx7)=42/56`
`2/9=(2xx7)/(9xx7)=14/63`
`49/56=(49:7)/(56:7)=7/8`
A -17/30 + 11/15 - 7/12
1/2+3/4-(3/4-4/5)
-7/25×11/13+ -7/25×2/13-18/25
(-3,2)+ -15/64+(0,8-2 4/15)÷3 2/3
-5/9+5/9÷(1 2/3- 2 1/12)
-5/7×2/11+ -5/7×9/11+ 1 5/7
(3/8+ -3/4+7/12)÷5/6+1/2
50%×1 1/3×10×7/35×0,75
Mn giúp mk với
\(\dfrac{1}{2}+\dfrac{3}{4}-\left(\dfrac{3}{4}-\dfrac{4}{5}\right)\)
=\(\dfrac{1}{2}+\dfrac{3}{4}-\dfrac{3}{4}+\dfrac{4}{5}\)
=\(\left(\dfrac{1}{2}+\dfrac{4}{5}\right)+\left(\dfrac{3}{4}-\dfrac{3}{4}\right)\)
=\(\left(\dfrac{5}{10}+\dfrac{8}{10}\right)+0\)
=\(\dfrac{13}{10}\)
\(-\dfrac{7}{25}.\dfrac{11}{13}+\left(-\dfrac{7}{25}\right).\dfrac{2}{13}-\dfrac{18}{25}\)
=\(-\dfrac{7}{25}.\cdot\left(\dfrac{11}{13}+\dfrac{2}{13}\right)-\dfrac{18}{25}\)
=\(-\dfrac{7}{25}.1-\dfrac{18}{25}\)
=\(-\dfrac{7}{25}-\dfrac{18}{25}\)
=\(-\dfrac{25}{25}\) = \(-1\)
(-3,2) +\(\dfrac{15}{64}+\left(0.8-2\dfrac{4}{15}\right):3\dfrac{2}{3}\)
=\(-\dfrac{16}{5}+\dfrac{15}{64}+(\dfrac{4}{5}-\dfrac{34}{15}):\dfrac{11}{3}\)
=\(-\dfrac{16}{5}+\dfrac{15}{64}+(-\dfrac{22}{5}):\dfrac{11}{3}\)
=\(-\dfrac{16}{5}+\dfrac{15}{64}+\dfrac{-2}{5}\)
=(\(-\dfrac{16}{5}+\dfrac{-2}{5}\)) +\(\dfrac{15}{64}\)
=\(-\dfrac{18}{5}+\dfrac{15}{64}\)
\(-\dfrac{1152}{320}+\dfrac{75}{320}\)
\(-\dfrac{1077}{320}\)
Tính thuận tiện
a) A=(15 - 6 13/18) : 11 1/27 - 2 1/8 : 1 11/40
b) B=(-3,2) . -15/64 + (0,8 - 2 4/15): 3 2/3
c) C= -7/9 . 4/11 + -7/9. 7/11 + 5 7/9
d) D= 50% .1 1/3 . 10 . 7/35 . 0,75
e) E= (2/5)^2 + 5 1/2 (4,5 - 2) + 23/-4
a: \(=\left(15-6-\dfrac{13}{18}\right):\dfrac{298}{27}-\dfrac{17}{8}:\dfrac{51}{40}\)
\(=\dfrac{149}{18}\cdot\dfrac{27}{298}-\dfrac{5}{3}=\dfrac{3}{2}-\dfrac{5}{3}=\dfrac{9-10}{6}=\dfrac{-1}{6}\)
b: \(=\dfrac{-16}{5}\cdot\dfrac{-15}{64}+\dfrac{-22}{15}:\dfrac{11}{2}\)
\(=\dfrac{3}{4}-\dfrac{4}{15}=\dfrac{29}{60}\)
c: \(=\dfrac{-7}{9}\left(\dfrac{4}{11}+\dfrac{7}{11}\right)+5+\dfrac{7}{9}=\dfrac{-7}{9}+\dfrac{7}{9}+5=5\)
d: \(=\dfrac{1}{2}\cdot\dfrac{4}{3}\cdot10\cdot\dfrac{1}{5}\cdot\dfrac{3}{4}=1\)
e: \(=\dfrac{4}{25}+\dfrac{11}{2}\cdot\dfrac{5}{2}+\dfrac{-23}{4}=\dfrac{204}{25}\)
a: =35/17-18/17-9/5+4/5
=1-1=0
b: =-7/19(3/17+8/11-1)
=7/19*18/187=126/3553
c: =26/15-11/15-17/3-6/13
=1-6/13-17/3
=7/13-17/3=-200/39
4 [-2(8:4)+15(-3)-(-12)
3(25:5-14:2)-5(6:2)
[-15:(-3)]-3[2(5-9):3]
-16:(-4)[7-2(15:3)]
-7[8-3(14:7)-12:(-4)]-3(-2)
2[3-9:(-3)+2(5-7)]-18:(-9)
-16:(-8)+5[3-15:5+2] (-3+4)
4[-2(8:4)+15:(-3)-(-12)
3(25:5-14:2)-5(6:2)
[-15:(-3)]-3[2(5-9):3)]
-16:(-4)[7-2(15:3)]
-7[8-3(14:7)-12:(-4)]-3(-2)
2[3-9:(-3)+2(5-7)]-18:(-9)
-16:(-8)+5[3-15:5+2] (-3+4)
bài 1
4/7+4
3+6/11
3-5/7
21/9-2
15/24+2
63/45-20/25
3/4-2/8
6/7-5/8
37/45-5/9
46/39-11/13
5/12+3/4+1/3
1/2+3/7+11/14
7/10-(1/5+1/4)
15/4-2/3-3/4
`4/7+4`
`=4/7+4/1`
`=4/7+28/7`
`=32/7`
__
`3+6/11`
`=33/11+6/11`
`=39/11`
__
`3-5/7`
`=3/1-5/7`
`=21/7-5/7`
`=16/7`
__
`21/9-2`
`=21/9-18/9`
`=3/9`
`=1/3`
__
`15/24+2`
`=15/24+48/24`
`=63/24`
`=21/16`
__
`63/45-20/25`
`=63/45-4/5`
`=63/45-36/45`
`=27/45`
`=9/15`
__
`3/4-2/8`
`=3/4-1/4`
`=2/4`
__
`6/7-5/8`
`=48/56-35/56`
`=13/56`
__
`37/45-5/9`
`=37/45-25/45`
`=12/45`
`=4/15`
__
`46/39-11/13`
`=46/39-33/39`
`=13/39`
`=1/2`
__
`5/12+3/4+1/3`
`=5/12+9/12+4/12`
`=14/12+4/12`
`=18/12`
`=3/2`
__
`1/2+3/7+11/14`
`=7/14+6/14+11/14`
`=13/14+11/14`
`=24/14`
`=12/7`
__
`7/10-(1/5+1/4)`
`=7/10-(4/20+5/20)`
`=7/10-9/20`
`=14/20-9/20`
`=5/20`
`=1/4`
__
`15/4-2/3-3/4`
`=(15/4-3/4)-2/3`
`=12/4-2/3`
`=3-2/3`
`=9/3-2/3`
`=7/3`
Thực hiện phép tính
a) 5/9 + 4/9 . 3/7 + 4/9 . 4/7
b) -2/5 . 5/2 + -1/6 . 3/7 + 3/6 . 1/7
c) -4/11 . 7/15 + 4/11 . -8/15 + 5/11
Hicc mình hông còn tgian mấy bạn giúp minh 2 câu thui cũng đc ạk
a) 5/9 + 4/9 . 3/7 + 4/9 . 4/7
= 5/9 + 4/9 . (3/7 + 4/7)
= 5/9 + 4/9 . 1
= 5/9 + 4/9
= 1
mình lười nghĩ lắm sorry