Thực hiện phép tính ( tính nhanh nếu có thể )
1, 11 3/13-(2 4/7+5 3/13)
2, 19 5/8:7/12+(-15 1/4):7/12
3, 2/5.1/3-2 2/15:1/5+3/5.1/3
4, (3 1/3+2,5):(3 1/6-4 1/5)-11/31
5, 75%-1 1/5+0,5:5/12-(-1/2)2
ĐỀ CƯƠNG ÔN TẬP TOÁN 6 I/ PHẦN SỐ HỌC 1/ Dạng toán thực hiện phép tính – tính nhanh nếu có thể - a) - 5/7 * 2/11 - 5/7 * 9/11 + 1 5/7 b) 11 3/13 - (2 4/7 + 5 3/13) c) 2/7 * .5 * 1/4 - 2/7 * .3 * 1/4 d) 5/7 * 1/3 - 5/7 * 1/4 - 5/7 * 1/12 75\%-1 1 2 +0,5: 5 12 -( -1 2 )^ 2 e) f) 7 19 . 8 11 + 7 19 , 3 11 - 12 19 g) - 5/12 * 2/11 - 5/12 * 9/11 + 5/12 h) - 5/7 * 2/11 - 5/7 * 9/11 + 1 5/7 i) 6 7 + 5 8 :5- 3 16 .(-2)^ 2 j) 8.(-5).(-4).2 ; *) 2 3 + 1 3 .( -2 3 + 5 6 ); 2 3 k) 1) - 2/5 + (- 5/9 + 2/5) m) 17/13 - (4/13 - 11)
Thực hiện phép tính ( tính nhanh nếu có thể )
1, [6+(1/2)3-|-0,5|]:3/12
2, 1/3+5/4:(-35/16)
3, 11 3/13-(2 4/7+5 3/13)
4, 1 3/7+(-1/3+2 4/7)
5, (6 4/9+3 7/11)-4 4/9
1 .
[ 6 + ( 1/2 ) 3 - /-0,5/ ] : 3/12
= [ 6 + 1/8 - ( -5/10 ) ] . 12/3
= [ 6 + 1/8 + 5/10 ] .4
= [ 6 + 1/8 + 1/2 ] .4
= [ 48/8 + 1/8 + 4/8 ] .4
= 53/8 . 4
= 53 . 1/2
= 53/2
2.
1/3 + 5/4 : (-35/16)
= 1/3 + 5/4 . ( 16/-35 )
= 1/3 + 1 . 4/4 . (-7 )
= 1/3 + 4/28
= 1/3 + 1/7
= 7/21 + 3/21
= 10/21
3 .
11 3/13 - ( 2 4/7 + 5 3/13 )
= 11 3/13 - 2 4/7 - 5 3/13
= { [ ( 11 - 5 ) . ( 3/13 - 3/13 ) } - 2 4/7
= ( 6 . 0 ) - 2 4/7
= 0 - 18/7
= 18/7
4 .
1 3/7 + (-1/3 + 2 4/7 )
= 1 3/7 + ( -1 )/3 + 2 4/7
={ [ ( 1 + 2 ) . ( 3/7 + 4/7 ) } + ( -1 )/3
= ( 3 . 1 ) + ( -1 )/3
= 3 + ( -1 )/3
= 9/3 + ( -1 )/3
= 8/3
5 .
( 6 4/9 + 3 7/11 ) - 4 4/9
= 6 4/9 + 3 7/11 - 4 4/9
= { ( 6 - 4 ) . ( 4/9 - 4/9 ) } + 3 7/11
= ( 2 . 0 ) + 3 7/11
= 0 + 40/11
= 40/11
Nếu đúng thì k cho mình nha !
1, Thực hiện phép tính ( tính hợp lý nếu có thể) A, -1/12+4/3 B,(-4/14-3/15)-(1/5-20/35- -1)7 C, 3/5+ -5/20+30/75+ -7/4 D, 5/6. -12/13 + 7/13 E, 2/-9 - 5/-36 - 1/4 F, 2/23 +-5/12+7/18+21/23+ -7/12
c) Ta có: \(\dfrac{3}{5}+\dfrac{-5}{20}+\dfrac{30}{75}+\dfrac{-7}{4}\)
\(=\dfrac{3}{5}+\dfrac{2}{5}+\dfrac{-1}{4}+\dfrac{-7}{4}\)
\(=1-2=-1\)
Giải:
a)-1/12+4/3=-1/12+16/12=15/12=5/4
b)(-4/14-3/15)-(1/5-20/35-(-1)).7
=-17/35-22/35.7
=-17/35-22/5
=-171/35
c)3/5+-5/20+30/75+-7/4
=3/5+-1/4+2/5+-7/4
=(3/5+2/5)+(-1/4+-7/4)
=1+-2
=-1
d)5/6.-12/14+7/13
=-5/7+7/13
=-16/91
e)2/-9-5/-36-1/4
=-1/12-1/4
=-1/3
f)2/23+-5/12+7/18+21/23+-7/12
=(2/23+21/23)+(-5/12+-7/12)+7/18
=1+-1+7/18
=7/18
Tính hợp lí nếu có thể :
56 : 54 + 23. 22 -225 : 152
7/19 . 8/113/11 .7/19 . -12/19
-7/25 . 39/ 14 . 50/78
(3/8 +-3/4 +7/12):5/6+1/2
2/5.1/3-2/15:1/5+3/5.1/3
a: \(=5^2+2^5-1=25+32-1=25+31=56\)
c: \(=\dfrac{-7}{25}\cdot\dfrac{39}{14}\cdot\dfrac{50}{78}\)
\(=\dfrac{-7}{14}\cdot\dfrac{39}{78}\cdot\dfrac{50}{25}=\dfrac{-1}{2}\)
d: \(=\left(\dfrac{3}{8}-\dfrac{3}{4}+\dfrac{7}{12}\right)\cdot\dfrac{6}{5}+\dfrac{1}{2}\)
\(=\dfrac{9-18+14}{24}\cdot\dfrac{6}{5}+\dfrac{1}{2}\)
\(=\dfrac{1}{4}+\dfrac{1}{2}=\dfrac{3}{4}\)
thực hiện phép tính :
a) 11 và 3/4 ( 6 và 5/6 - 4 và 1/2 + 1 và 2/3 )
b) ( 5 và 7/8 - 2 và 1/4 - 0,5 ) : 2 và 23 / 26
c) ( 17 và 13/15 - 3 và 3/7 ) - ( 2 và 12/15 - 4 )
d ) 2 và 2/3 . ( -4 /5 . 0,375 . ( -10) . ( -15/24)
Giải:
a) \(11\dfrac{3}{4}.\left(6\dfrac{5}{6}-4\dfrac{1}{2}+1\dfrac{2}{3}\right)\)
\(=\dfrac{47}{4}.\left(\dfrac{41}{6}-\dfrac{9}{2}+\dfrac{5}{3}\right)\)
\(=\dfrac{47}{4}.4\)
\(=47\)
b) \(\left(5\dfrac{7}{8}-2\dfrac{1}{4}-0,5\right):2\dfrac{23}{26}\)
\(=\left(\dfrac{47}{8}-\dfrac{9}{4}-\dfrac{1}{2}\right):\dfrac{75}{26}\)
\(=\dfrac{25}{8}:\dfrac{75}{26}\)
\(=\dfrac{13}{12}\)
c) \(\left(17\dfrac{13}{15}-3\dfrac{3}{7}\right)-\left(2\dfrac{12}{15}-4\right)\)
\(=\dfrac{268}{15}-\dfrac{24}{7}-\dfrac{14}{5}+4\)
\(=\left(\dfrac{268}{15}-\dfrac{14}{5}\right)+\left(\dfrac{-24}{7}+4\right)\)
\(=\dfrac{226}{15}+\dfrac{4}{7}\)
\(=\dfrac{1642}{105}\)
d) \(2\dfrac{2}{3}.\left(\dfrac{-4}{5}.0,375.-10.\dfrac{-15}{24}\right)\)
\(=\dfrac{8}{3}.\left(\dfrac{-4}{5}.\dfrac{3}{8}.-10.\dfrac{-5}{8}\right)\)
\(=\left(\dfrac{8}{3}.\dfrac{3}{8}\right).\left(\dfrac{-4}{5}.\dfrac{-5}{8}.-10\right)\)
\(=1.-5\)
\(=-5\)
Chúc bạn học tốt!
( tính nhanh )
a,8/40+-14/35-12/60 b,5/7.5/11+5/7.5/11-5/7.14/11 c,19 5/8: 7/12-15 1/4:7/12
d, 2/5.1/3-2/15:1/5+ 3/5.1/3 e,4/9.19 1/3 - 4/9.39 1/3 g,81.17-15.81/81.17-81.15
a) \(\frac{8}{40}+\frac{-14}{35}-\frac{12}{60}\)
= \(\frac{1}{5}-\frac{2}{5}-\frac{1}{5}\)
= \(\left(\frac{1}{5}-\frac{1}{5}\right)-\frac{2}{5}\)
= \(-\frac{2}{5}\)
b) 5/7.5/11 + 5/7.5/11 - 5/7.14/11
= 5/7.(5/11 + 5/11 - 14/11)
= 5/7.(-4/11)
= -20/77
c) \(19\frac{5}{8}:\frac{7}{12}-15\frac{1}{4}:\frac{7}{12}\)
= \(\left(19\frac{5}{8}-15\frac{1}{4}\right):\frac{7}{12}\)
= \(\frac{35}{8}:\frac{7}{12}\)
= \(\frac{15}{2}\)
d) 2/5.1/3 - 2/15 : 1/5 + 3/5.1/3
= (2/5 + 3/5).1/3 - 2/15 . 5
= 1.1/3 - 2/3
= 1/3 - 2/3
= -1/3
e) \(\frac{4}{9}.19\frac{1}{3}-\frac{4}{9}.39\frac{1}{3}\)
= \(\frac{4}{9}.\left(19\frac{1}{3}-39\frac{1}{3}\right)\)
= \(\frac{4}{9}.\left(-20\right)\)
= \(\frac{-80}{9}\)
g) \(\frac{81.17-15.81}{81.17-81.15}\)
= 1
a)8/40+-14/35-12/60=1/5+(-2/5)-1/5=-2/5
b)5/7.5/11+5/7.5/11-5/7.14/11=5/7.(5/11+5/11-14/11)=5/7.-4/11=-20/77
c)19 5/8:7/12-15 1/4:7/12=(19 5/8-15 1/4):7/12=35/8.12/7=15/2
d)2/5.1/3-2/15:1/5+3/5.1/3=2/15-2/15.5/1+3/15=2/15.2/3+1/5=-5/15=-1/5
e)4/9.19 1/3-4/9.39 1/3=4/9.(19 1/3- 39 1/3)=4/9. 20=80/9
g)81.17-15.81/81.17-81.15=81.(17-15)-15.1.17=81.2-255=162-255=-90
Chúc bạn học giỏi!!! hihi
Thực hiện phép tính(tính hợp lí nếu có thể)
4/5+(-5)/4 -1/3+2/5-5/6 2/3-5/7.14/25 (2/5-5/6):8/15-(-1)^2
-3/13+(-7)/17+(-5)/19+(-10)/13+24/17+(-14)/19
\(\dfrac{4}{5}\)+\(\dfrac{-5}{4}\)=\(\dfrac{0}{4}\)
\(\dfrac{-1}{3}\)+\(\dfrac{2}{5}-\dfrac{5}{6}\)=\(\dfrac{-10}{30}+\dfrac{12}{30}-\dfrac{25}{30}\)=\(\dfrac{-23}{30}\)
\(\dfrac{2}{3}-\dfrac{5}{7}.\dfrac{14}{25}\)=\(\dfrac{2}{3}-\dfrac{2}{5}\)=\(\dfrac{10}{15}-\dfrac{6}{15}\)=\(\dfrac{4}{15}\)
a: \(=\dfrac{16-25}{20}=\dfrac{-9}{20}\)
b: \(=\dfrac{-10}{30}+\dfrac{12}{30}-\dfrac{25}{30}=-\dfrac{23}{30}\)
c: \(=\dfrac{2}{3}-\dfrac{1}{5}\cdot2=\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{10-6}{15}=\dfrac{4}{15}\)
d: \(=\dfrac{12-25}{30}\cdot\dfrac{15}{8}-1=\dfrac{-13}{16}-1=\dfrac{-29}{16}\)
e: \(=\dfrac{-3}{13}-\dfrac{10}{13}-\dfrac{7}{17}+\dfrac{24}{17}-\dfrac{5}{19}-\dfrac{14}{19}=-1\)
bài 2 . thực hiện phép tính
a. -1,75-(-1/9-2 1/18)
b. -1/12- (2 5/8-1/3)
c. -5/6-(-3/8+1/10)
Bài 3 :tìm x ,biết :
a. 11/13-(5/42-x)=(-15/28-11/13)
b. x+1/3=2/5-(-1/3)
c. 3/7-x=1/4-(-3/5)
a.-1,75-(-\(\dfrac{1}{9}\)-2\(\dfrac{1}{8}\))
-1,75-\(\dfrac{1}{9}+\dfrac{17}{8}\)
\(-\dfrac{7}{4}-\dfrac{1}{9}+\dfrac{17}{8}\)
\(\dfrac{-126}{72}-\dfrac{8}{72}+\dfrac{153}{72}\)
=\(\dfrac{19}{72}\)
b.\(\dfrac{-1}{12}-\left(2\dfrac{5}{8}-\dfrac{1}{3}\right)\)
\(\dfrac{-1}{12}-\left(\dfrac{21}{8}-\dfrac{1}{3}\right)\)
\(\dfrac{-1}{12}-\dfrac{21}{8}+\dfrac{1}{3}\)
\(\dfrac{-2}{24}-\dfrac{63}{24}+\dfrac{64}{24}\)
=\(\dfrac{-1}{24}\)
\(\dfrac{-5}{6}-\left(\dfrac{-3}{8}+\dfrac{1}{10}\right)\)
\(\dfrac{-5}{6}-\dfrac{-3}{8}-\dfrac{1}{10}\)
Thực hiện phép tính ( tính nhanh nếu có thể )
-4/11 + 5/6 + 7/11 - 5/6
-5/6 . 7/13 + 19/13 : 6/-5 + 2/5
3/7 . (0,5 + 1 1/2) - 2/7 : 25%
Pleasee giúp mình với mình cần gấp lắm. Mình sẽ tick nhé
-4/11+5/6+7/11-5/6
=(-4/11+7/11)+(5/6-5/6)
=3/11+0
=3/11
Làm là giúp đủ 3 câu hộ mình. 1 câu k k đâu !
3/7*(0,5+11/2)-2/7:25%
=3/7*(0,5+11/2)-2/7:1/4
=3/7*(0,5+11/2)-2/7*4
=3/7*(1/2+11/2)-2/7*4
=3/7*6-2/7*4
=18/7-8/7
=10/7