1 1/2+3/14:9/7-75%
4/7-1/3.......1/2-2/9 7/5-20/25........1/5+4/10 125/100-48/64........6/7-14/28 45/75+22/33.....4/5+4/6 À ĐÂY LÀ BÀI >
\(\dfrac{4}{7}-\dfrac{1}{3}< \dfrac{1}{2}-\dfrac{2}{9}\)
\(\dfrac{125}{100}-\dfrac{48}{64}< \dfrac{6}{7}-\dfrac{14}{28}\)
\(\dfrac{7}{5}-\dfrac{22}{25}=\dfrac{1}{5}+\dfrac{4}{10}\)\(\dfrac{45}{75}+\dfrac{22}{33}>\dfrac{4}{5}+\dfrac{4}{6}\)
Tính hợp lí:
a, 75. ( \(-2\frac{3}{25}+7\frac{2}{75}-5\frac{4}{15}\) )
b, \(45.\left(5\frac{4}{15}-4\frac{7}{9}-1\frac{8}{45}\right)\)
c, \(\frac{-5}{8}+\frac{14}{18}-\frac{3}{8}+\frac{2}{9}-\frac{1}{2006}\)
d, \(\frac{15}{29}-\frac{8}{7}+\frac{16}{14}+\frac{14}{29}-\frac{3}{8}\)
e, \(\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{49.51}\)
Bài 442: Tính hợp lý:
1. 1/3 . 4/5 + 1/3 . 6/5 - 1/3
2. 3/7 . 9/26 - 1/14 . 1/13
3. 15(1/5 - 7/15 + 17/3)
4. 38(2và1/19 - 5và7/38)
5. 75( - 4/25 + 7và1/15 - 5và7/75)
\(1)\frac{1}{3}.\frac{4}{5}+\frac{1}{3}.\frac{6}{5}-\frac{1}{3}\)
\(=\frac{1}{3}\left(\frac{4}{5}+\frac{6}{5}\right)\)
\(=\frac{1}{3}.2\)
\(=\frac{2}{3}\)
\(1)\)\(\frac{1}{3}.\frac{4}{5}+\frac{1}{3}.\frac{6}{5}-\frac{1}{3}\)
\(=\frac{1}{3}.\left(\frac{4}{5}+\frac{6}{5}-1\right)\)
\(=\frac{1}{3}.\left(\frac{4}{5}+\frac{6}{5}-\frac{5}{5}\right)\)
\(=\frac{1}{3}.1\)
\(=\frac{1}{3}\)
\(2)\)\(\frac{3}{7}.\frac{9}{26}-\frac{1}{14}.\frac{1}{13}\)
\(=\frac{1}{7}.\frac{27}{26}-\frac{1}{7}.\frac{1}{26}\)
\(=\left(\frac{27}{26}-\frac{1}{26}\right).\frac{1}{7}\)
\(=1.\frac{1}{7}\)
\(=\frac{1}{7}\)
\(3)\)\(15\left(\frac{1}{5}-\frac{7}{15}+\frac{17}{3}\right)\)
\(=3-7+85\)
\(=81\)
\(4)\)\(38\left(2\frac{1}{19}-5\frac{7}{38}\right)\)
\(=38\left(\frac{39}{19}-\frac{197}{38}\right)\)
\(=78-197\)
\(=-119\)
\(5)\)\(75\left(\frac{-4}{25}+7\frac{1}{15}-5\frac{7}{75}\right)\)
\(=75\left(\frac{-4}{25}+\frac{106}{15}-\frac{382}{75}\right)\)
\(=-12+530-382\)
\(=136\)
Ddaeng
1, \(\frac{1}{3}.\frac{4}{5}+\frac{1}{3}.\frac{6}{5}-\frac{1}{3}\)
\(=\frac{1}{3}.\left(\frac{4}{5}+\frac{6}{5}\right)-\frac{1}{3}\)
\(=\frac{1}{3}.2-\frac{1}{3}\)
\(=\frac{2}{3}-\frac{1}{3}\)
\(=\frac{1}{3}\)
2, \(\frac{3}{7}.\frac{9}{26}-\frac{1}{14}.\frac{1}{13}\)
\(=\frac{1}{7}.3.\frac{9}{26}-\frac{1}{7}.\frac{1}{2}.\frac{1}{13}\)
\(=\frac{1}{7}.\frac{27}{26}-\frac{1}{7}.\frac{1}{26}\)
\(=\frac{1}{7}.\left(\frac{27}{26}-\frac{1}{26}\right)\)
\(=\frac{1}{7}.1\)
\(=\frac{1}{7}\)
3, \(15.\left(\frac{1}{5}-\frac{7}{15}+\frac{17}{3}\right)\)
\(=15.\frac{1}{5}-15.\frac{7}{15}+15.\frac{17}{3}\)
\(=3-7+85\)
\(=81\)
4, \(38.\left(2\frac{1}{19}+5\frac{7}{38}\right)\)
\(=38.\left(\frac{39}{19}+\frac{197}{38}\right)\)
\(=38.\frac{39}{19}+38.\frac{197}{38}\)
\(=78+197\)
\(=275\)
5, \(75.\left(\frac{-4}{25}+7\frac{1}{15}-5\frac{7}{75}\right)\)
\(=75.\left(\frac{-4}{25}+\frac{106}{15}-\frac{382}{75}\right)\)
\(=75.\frac{-4}{25}+75.\frac{106}{15}-75.\frac{382}{75}\)
\(=-12+530-382\)
\(=136\)
Tính:a,(-40/41.0,32.17/20):64/75
b,-10/11.8/9+7/18.10/11
c,3/14:1/28-13/21:1/28+29/42:1/28-8
d,-12/7.15+2/7.(-15)+(-105).(2/3-4/5+1/7)
Tính nhanh
( 24 x 5 - 12 x 10) x ( 1+2+3+4+5+6+7+8+9)
30 x 25 x 7 x 8/ 75 x 8 x 12 x 14
\((\)125-120\()\)x45
5x45=225
\(\dfrac{30x25x7x8}{75x8x12x14}\)=\(\dfrac{10\cdot1\cdot7\cdot1}{1\cdot1\cdot1\cdot12\cdot2}\)=\(\dfrac{70}{24}\)
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
ài 1: Tính giá trị của biểu thức sau:
1)2763 + 152 2)(-7) + (-14)
3)(-35) + (-9) 4)(-5) + (-248)
5)(-23) + 105 6)78 + (-123)
7)23 + (-13) 8)(-23) + 13
9)26 + (-6) 10) (-75) + 50
11)80 + (-220) 12) (-23) + (-13)
13)(-26) + (-6) 14 (-75) + (-50)
15)-18 + (-12) 16)17 + -33
17)(– 20) + -88 18) -3 + 5
19)-37 + 15 20)-37 + (-15)
21)(--32) + 5 22)(--22)+ (-16)
23)(-23) + 13 + ( - 17) + 57 24)14 + 6 + (-9) + (-14)
25) (-123) +-13+ (-7) 26) 0+45+(--455)+-796
câu nầy hơn khó nên mình ko giải đc bạn đợ mình giải đã
1) 2763 + 152 = 2951
2)(-7) + (-14) = -21
3)(-35) + (-9) =-44
4) (-5) + (-248) = -253
Tính hơp. lý nêu' có thê? :
a) 2/7 + -3/14 - 5/2
b) 4/13 + -11/5 + 9/13 + 6/5 - 75%
c) 19 5/8 . 7/12 - 15 1/4 . 7/12
d) 8 2/7 - [ 3 4/9 + 4 2/7 ]
1 thực hiện phép tính
a/5/3-1/4+-3/12
b/60%+2 1/5 -0,3.2/3
c/ 5/14.2/9-5/14+5/14- -11/9
2/ tính giá trị biểu thức
a/x+5/6 =1/8 c/ [3/5-1/5 x]= 75%= [-1/2]
b/-3x -7/2=-0,8
1 thực hiện phép tính
a/5/3-1/4+-3/12
\(= \dfrac{5}{3}-\dfrac{1}{4}-\dfrac{3}{12}\)
= \(\dfrac{7}{6}\)
b/60%+2 1/5 -0,3.2/3
\(= \dfrac{3}{5}+\dfrac{11}{5}-\dfrac{1}{5}\)
\(= \dfrac{13}{5}\)
c/ 5/14.2/9-5/14+5/14- -11/9
\(= \dfrac{5}{63}+\dfrac{11}{9}\)
= \(\dfrac{82}{63}\)
2/ tính giá trị biểu thức
a/x+5/6 =1/8
\(<=> x=\dfrac{-17}{24}\)