đố các bạn:
\(\frac{144}{7}\): 36=...
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BỎ DẤU NGOẶC RỒI TÍNH :
1. - 7264 + ( 1543 + 7264 )
= ( - 7264 ) + 1543 + 7264
= [ ( - 7264 ) + 7264 ] + 1543
= 0 + 1543
= 1543
2. (144 - 97 ) - 144
= 144 + ( - 97 ) + (- 144 )
= [ 144 +( - 144) ] + ( -97 )
= 0 + (- 97)
= - 97
3. ( - 145 ) - ( 18 - 145 )
= ( -145 ) + ( - 18 ) + 145
= [ ( -145 ) + 145 ] + ( -18 )
= 0 + ( - 18)
= - 18
4. 111 + ( - 11 + 27 )
= 111 + ( - 11 ) + 27
= ( 111 + 27 ) + ( -11 )
= 138 + ( -11 )
= 127
5. ( 27 + 541 ) - ( 486 - 73 )
= 27 + 541 + ( - 486) + 73
= ( 27 + 73 ) + [ 541 + ( - 486 )]
= 100 + 55
= 155
6. ( 36 + 79 ) + ( 145 - 79 - 36)
= 36 + 79 + 145 + ( - 79 ) + ( - 36 )
= [ 36 + ( - 36)] + [ 79 + ( -79 )] + 145
= 0 + 0 + 145
= 145
7. 10 - [ 12 - ( -9 - 1) ]
= 10 + ( - 12 ) + 9 + ( -1 )
= ( 10 + 9 ) + [ ( -12 ) + ( - 1) ]
= 19 + ( - 13 )
= 6
8. ( 38 - 29 + 43 ) - (43 + 38 )
= 38 + ( - 29 ) 43 + ( -43 ) +( - 38)
= [ 38 + ( - 38 )] + [ 43 + ( - 43 ) ] + ( - 29 )
= 0 + 0 + ( - 29 )
= - 29
9. 274 - [ ( - 43 ) + 271 - ( - 17 )]
= 274 + 43 + ( - 271 ) + 17
= [ 274 + ( - 271 ) ] + ( 43 + 17 )
= 3 + 60
= 63
10. - 144 - [ 29 - ( + 144 ) - ( + 144 )
= ( - 144 ) + ( - 29 ) + 144 +( - 144 )
= [ ( - 144 ) + 144 ] + [ ( -29) + ( - 144 ) ]
= 0 + ( - 173 )
= - 173
k cho mk nếu đúng . Sai thì thôi nhé . ahihi
=
\(1.-7264+\left(1543+7264\right)\)
\(=-7264+1543+7264\)
\(=1543\)
\(2.\left(144-97\right)-144\)
\(=144-97-144\)
\(=-97\)
\(3.\left(-145\right)-\left(18-145\right)\)
\(=-145-18+145\)
\(=-18\)
\(4.111+\left(-11\right)+27\)
\(=111-11+27\)
\(=100+27\)
\(=127\)
\(5.\left(27+541\right)-\left(486-73\right)\)
\(=27+541-486+73\)
\(=\left(27+73\right)+\left(541-486\right)\)
\(=100+55\)
\(=155\)
các câu còn lại tương tự phá ngoặc ra nha
Ta có: \(A=\frac{1}{2^2}+\frac{1}{4^2}+\frac{1}{6^2}+\frac{1}{8^2}+\frac{1}{10^2}+\frac{1}{12^2}+\frac{1}{14^2}\)
\(=\frac{1}{2^2}\left(1+\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+\frac{1}{5^2}+\frac{1}{6^2}+\frac{1}{7^2}\right)\)
\(< \frac{1}{2^2}\left(1+\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}\right)\)
\(=\frac{1}{2^2}\left(1+1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}\right)\)
\(=\frac{1}{2^2}\left(2-\frac{1}{7}\right)=\frac{1}{2}-\frac{1}{28}< \frac{1}{2}\)
Vậy \(A< \frac{1}{2}\).
1/ - 7264 + ( 1543 + 7264 )
= - 7264 + 1543 + 7264
= ( - 7264 + 7264 ) + 1543
= 0 + 1543
= 1543
2/ ( 144 - 97 ) - 144
= 144 - 97 - 144
= ( 144 - 144 ) - 97
= 0 - 97
= - 97
3/ ( - 145 ) - ( 18 - 145 )
= - 145 - 18 - 145
= ( - 145 - 145 ) - 18
= ( - 290 ) - 18
= - 308
Thế thôi nhé
1/ - 7264 + ( 1543 + 7264 )
= - 7264 + 1543 + 7264
= ( - 7264 + 7264 ) + 1543
= 0 + 1543
= 1543
K mk nha
1 bài nha
Làm hết chắc mk chết
Ta thấy \(\frac{3}{4}=\frac{1}{1^2}-\frac{1}{2^2};\frac{5}{36}=\frac{1}{2^2}-\frac{1}{3^2};...\)
Tổng quát: \(\frac{2n+1}{n^2\left(n+1\right)^2}=\frac{\left(n+1\right)^2-n^2}{n^2\left(n+1\right)^2}=\frac{1}{n^2}-\frac{1}{\left(n+1\right)^2}\)
Đặt \(A=\frac{3}{4}+\frac{5}{36}+...+\frac{2n+1}{n^2\left(n+1\right)^2}\)
\(\Rightarrow A=1-\frac{1}{2^2}+\frac{1}{2^2}-\frac{1}{3^2}+...+\frac{1}{n^2}-\frac{1}{\left(n+1\right)^2}\)
\(A=1-\frac{1}{\left(n+1\right)^2}\)
Do \(\left(n+1\right)^2>0\Rightarrow A< 1.\)
-7264 + ( 1543 + 7264 )
=-7264 + 1543 + 7264
=1543
(144 - 97 ) -144
=144 - 97 - 144
=-97
( -145 ) - ( 18 -145 )
= -145 - 18 - 145
=-308
111 + ( -11 + 27 )
=111 - 11 + 27
=127
( 27+ 514 ) - (486-73)
=27 + 514 - 486 - 73
=-18
( 36 + 79 ) + ( 145 - 79 - 36 )
=36 + 79 + 145 - 79 - 36
=145
( 38 -29+ 43 ) - ( 43 + 38 )
=38 - 29 + 43 - 43 + 38
=47
271 - [ ( -43 ) + 271 - ( -17)]
= 271 + 43 + 271 + 17
=602
-144 - [ 29 - ( + 144 ) - ( + 144 ) ]
=-144 - 29 - 144 - 144
=-461
hok tốt !
a) -7264+(1543 +7264) b) (144-97)-144 c)(-145)-(18-145)
=(-7264)+1543+7264 =144-97-144 =(-145)-18+145
= [(-7264)+7264]+1543 =(144-144)-97 =[(-145)+145}-18
=0+1543 =0-97 = 0-18
=1543 = -97 = -18
\(G=\frac{3}{4}+\frac{5}{36}+\frac{7}{144}+....+\frac{2n+1}{n^2.\left(n+1\right)^2}=\frac{3}{1.4}+\frac{5}{4.9}+...+\frac{2n+1}{n^2\left(n^2+2n+1\right)}=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{9}+...+\frac{1}{n^2}-\frac{1}{n^2+2n+1}\)
\(=1-\frac{1}{n^2+n+1}\left(n>0\right)\Rightarrow1-\frac{1}{n^2+n+1}<1\)
Vậy G<1
Bài 1 : bỏ dấu ngoặc rồi tính.
1, -7264+(1543+7264)
\(=-7264+1543+7264\)
\(=-8807+7264\)
\(=-1543\)
2, ( 144-97) - 144
\(=144-97-144\)
\(=47-144\)
\(=-97\)
3, ( -145) - ( 18- 145)
\(=-145-18+145\)
\(=-163+145\)
\(=18\)
4, 111+ ( -11+27)
\(=111+\left(-11\right)+27\)
\(=100+27\)
\(=127\)
5, ( 27+ 514) -( 486-73)
\(=27+514-486+73\)
\(=541-486+73\)
\(=55+73\)
\(=128\)
6, ( 36 + 79) + ( 145-79-36)
\(=36+79+145-79-36\)
\(=115+145-79-36\)
\(=260-79-36\)
\(=145\)
7, 10-[12-(- 9-1)]
\(=10-12+9+1\)
\(=8\)
8, ( 38-29+43) -( 43+38)
\(=38-29+43-43-38\)
\(=-29\)
9, 271-[(-43)+271-(-17)]
\(=271+43-271+17\)
\(=60\)
10, -144-[29-(+144)-(+144)]
\(=-144-29-144-144\)
\(=-461\)
\(\frac{144}{7}:36\)
\(=\frac{144}{7}\cdot\frac{1}{36}\)
\(=\frac{144\cdot1}{7\cdot36}\)
\(=\frac{144}{252}\)
\(=\frac{4}{7}\)
chịu