Bai 1 : tinh
a . 6/7 + 5/8 : b. 3/5 - 3/8 ; c. 1/4 + 5/6 ; d. 4/9 - 1/6
Bai 2 : tinh
a. 3 + 2/5 ; b. 4 - 5/7 ;
c. 1 - [2/5 + 1/3] .
Bai:2 Tinh
a)3/5 + 4/7
b)2/3 - 3/9
c)2/5 * 8/11
d)3/7 : 5/14
e)3/8 + 6/15 :3/5
bai 1; 2/5 + 1/2 + 7/10 ; 4/9 + 11/8 - 5/6 ; 9/20 - 8/15 * 5/12
bai 2 ; 2/5 + 3/10 - 1/2 ; 8/11 + 8/33 * 3/4
bai 3 ; x - 3/4 = 1/2 ;
bai 4 ; tinh chu vi hinh chu nhat co chieu dai 4/5 m va chieu rong 2/3 m
bai 1 tinh nhanh
a . 1/5x6 +1/6x7+ 1/7x8 + 1/8x9 +1/9x10
b . 1/1x2 + 1/2x3 + ....... + 1/99x100
c . 2/3x5 + 2/5x7 + 2/7x8 + 2/8x9
d . 2/3x5 + 2/5x7 + .......+ 2/98x100
bai 2 tinh hop li
9/13 + 14/6 + 1/9 + 4/6 + 7/13 + 17/19
bai 3 dien dau ( > , < , = )
a . 3/4 + 5/2 ....... 5/8 + 2 3/5 ( hon so )
B . 3 1/5 - 8/3 ......... 17/5 - 2 12/5 hon so
c . 2 4/9 + 18/7......... 22/9 + 2 4/7
giup mk nha cac ban , mai mk phai nop bai roi toi nay mk se lay y kien cua cac ban , giup mk nha
b1
a) \(\dfrac{1}{5.6}+\dfrac{1}{6.7}+\dfrac{1}{7.8}+\dfrac{1}{8.9}+\dfrac{1}{9.10}\)
\(=\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{10}\)
\(=\dfrac{1}{5}-\dfrac{1}{10}\)
\(=\dfrac{2}{10}-\dfrac{1}{10}\)
\(=\dfrac{1}{10}\)
b) \(\dfrac{1}{1.2}+\dfrac{1}{2.3}+...+\dfrac{1}{99.100}\)
\(=\dfrac{1}{1}-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{99}-\dfrac{1}{100}\)
\(=\dfrac{1}{1}-\dfrac{1}{100}\)
\(=\dfrac{99}{100}\)
c) \(\dfrac{2}{3.5}+\dfrac{2}{5.7}+\dfrac{2}{7.9}+\dfrac{2}{9.11}\)
\(=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{11}\)
\(=\dfrac{1}{3}-\dfrac{1}{11}\)
\(=\dfrac{8}{33}\)
d) \(\dfrac{2}{3.5}+\dfrac{2}{5.7}+...+\dfrac{2}{99.101}\)
\(=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+...+\dfrac{1}{99}-\dfrac{1}{101}\)
\(=\dfrac{1}{3}-\dfrac{1}{101}\)
\(=\dfrac{98}{303}\)
bai 1 _dat tinh roi tinh
a] 27 gio 45 phut :3
b] 7.2 gio :3
c] 38gio24phut :6
d] 17.6phut :4
bai 2 _dien dau >,<,= thich hop vao cho cham
a] 5 phut 24 giay *7........3 gio 15 phut : 5
b] 8 gio 6 phut + 4 gio 5 phut........12 gio 51 phut - 3 gio 12 phut
bai 3 tinh
a] 4 gio 15 phut *3 + 1 gio 42 phut *2
b] (21 gio 17 phut -5 gio 12 phut ) :5
bai 4 _ 1 nguoi di bo moi gio di duoc 5km. hoi nguoi do di quang duong 8km het b/n thoi gian?
bai 5_ 1 nguoi tho lam viec tu 8 gio den 12 gio duoc 5 san pham. hoi voi muc lam nhu the, nguoi do lam 6 san pham het b/n thoi gian?
uk thi nhieu nhung cac ban co giup miik nha
bai 1:tinh nhanh hon so
a, 11 2/9+8 3/5+8 7/9+ 1 2/5
b, 4 2/3+5 1/2+1/3+4 1/2
c, 19 2/7+5 3/4+4 1/4-9 2/7
bai 2:hinh chu nhat co chieu dai 2 3/4m, chieu rong kem chieu dai la 1 1/2m. tinh chu vi va dien tich hinh chu nhat do.
1. \(11\frac{2}{9}+8\frac{3}{5}+8\frac{7}{9}+1\frac{2}{5}\)
\(=\frac{101}{9}+\frac{43}{5}+\frac{79}{9}+\frac{7}{5}\)
\(=\left(\frac{101}{9}+\frac{79}{9}\right)+\left(\frac{43}{5}+\frac{7}{5}\right)\)
\(=20+10\)
\(=30\)
\(4\frac{2}{3}+5\frac{1}{2}+\frac{1}{3}+4\frac{1}{2}\)
\(=\frac{14}{3}+\frac{11}{2}+\frac{1}{3}+\frac{9}{2}\)
\(=\left(\frac{14}{3}+\frac{1}{3}\right)+\left(\frac{11}{2}+\frac{9}{2}\right)\)
\(=5+10\)
\(=15\)
Phần c bạn làm tương tự .
2. Đổi : \(2\frac{3}{4}m=\frac{11}{4}m=275m;1\frac{1}{2}m=\frac{3}{2}m=150m\)
Chiều rộng hình chữ nhật đó là :
275 - 150 = 125 ( m )
Chu vi hình chữ nhật đó là :
( 275 + 125 ) x 2 = 800 ( m )
Diện tích hình chữ nhật đó là :
275 x 125 = 34 375 ( m2 )
Đ/S : ...
bài 1:
a,11 2/9 + 8 7/9 + 1 2/5
=(11 2/9 + 8 7/9) + (8 3/5 + 1 2/5)
=20 + 10
=30.
b,4 2/3 + 5 1/2 + 1/3 + 4 1/2
=(4 2/3 + 1/3)+(5 1/2 + 4 1/2)
=5 + 10
=15.
c,19 2/7 + 5 3/4 + 4 1/4 - 9 2/7
=(19 2/7 - 9 2/7) + (5 3/4 + 4 1/4)
=10 + 10
=20.
bài 2:
2 3/4m = 275m
1 1/2m = 150m
Chiều rộng hình chữ nhật là:
275 - 150 = 125 (m)
Chu vi hình chữ nhật là:
(275+125)*2=800(m)
Diện tích hình chữ nhật là:
125 * 275 = 34375 (m)
Đáp số: 34375 m.
bai 1 : tinh nhanh :
a) -3/7+ 15/26 - (2/13 - 3/7 ) b) 2.3/7+(2/9-1\(\frac{3}{7}\)) - 5/3 : 1/9 c) -11/23 . 6/7 + 8/7 .-11/23 - 1/23 d) ( 377/231 - 123/89 + 34 /701 ) . ( 1/6 - 1/8 -1 /24)
bai 2 . tim so x biet :
a ) 2/3x - 3/2x = 5/12 b) 2/5 + 3/5 . ( 3x-3,7) = -53/10 c) 7/9:(2+3/4x)+5/9=23/27 d,-2/3.x +1/5=3/10 e, /x/-3/4=5/3
f, /2x-1/3/+5/6=1
Bai 1 : Tinh
a) 12 . 52
b) 704 : 82
c) 22 . 72
d) ( 96 : 24)3
Bai 2 So sanh cac ket qua
a) 63 : 33 va ( 6 : 3 )3
b) 102 : 52 va ( 10 : 5 )2
tinh
a 7/15 + (5/6 - 1/3) =
b 4/7 *21/16 : 5/8 =
c 15/8 - 4/9 * 6/8+ 1/6 =
d 5/12+(3/4 + 2/3 ) : 34/3 =
a 7/15 + (5/6 - 1/3) = 7/15 + 1/2 = 14/30 + 15/30 = 29/30
b 4/7 *21/16 : 5/8 = 3/4 : 5/8 = 6/5
c 15/8 - 4/9 * 6/8+ 1/6 =15/8 - 1/3 + 1/6 = 37/24 + 1/6 = 41/24
d 5/12+(3/4 + 2/3 ) : 34/3 =
a/\(\frac{7}{15}+\left(\frac{5}{6}-\frac{1}{3}\right)=\frac{7}{15}+\frac{1}{2}=\frac{29}{30}\)
b/\(\frac{4}{7}\cdot\frac{21}{16}:\frac{5}{8}=\frac{4}{7}\cdot\frac{2}{16}\cdot\frac{8}{5}=\frac{4}{35}\)
c/\(\frac{15}{8}-\frac{4}{9}\cdot\frac{6}{8}+\frac{1}{6}=\frac{15}{8}-\frac{1}{3}+\frac{1}{6}=\frac{41}{24}\)
d/ \(\frac{5}{12}+\left(\frac{3}{4}+\frac{2}{3}\right):\frac{34}{3}=\frac{5}{12}+\frac{17}{12}:\frac{34}{3}=\frac{5}{12}+\frac{1}{8}=\frac{13}{24}\)
a/ \(\frac{7}{15}+\left(\frac{5}{6}-\frac{1}{3}\right)\)
= \(\frac{7}{15}+\frac{1}{2}\)
= \(\frac{29}{30}\)
b/ \(\frac{4}{7}.\frac{21}{16}:\frac{5}{8}\)
= \(\frac{4}{7}.\frac{21}{16}.\frac{8}{5}\)
= \(\frac{6}{5}\)
c/ \(\frac{15}{8}-\frac{4}{9}.\frac{6}{8}+\frac{1}{6}\)
= \(\frac{15}{8}-\frac{1}{3}+\frac{1}{6}\)
= \(\frac{41}{24}\)
d/ \(\frac{5}{12}+\left(\frac{3}{4}+\frac{2}{3}\right):\frac{34}{3}\)
= \(\frac{5}{12}+\frac{17}{12}\)\(:\frac{34}{3}\)
= \(\frac{5}{12}+\frac{1}{8}\)
= \(\frac{13}{24}\)
bai 1: tinh hop li
A) 100 + (-3) . (-5) - (-2)
B) -2 - 4 - 6 - 8 - 10 - 12 - 14
A) \(100+\left(-3\right).\left(-5\right)-\left(-2\right)=100+\left(\left(-3\right).\left(-5\right)\right)+2=100+15+2=117\)
B) \(-2-4-6-8-10-12-14=\left(-2-4\right)+\left(-6-14\right)+\left(-8-12\right)+\left(-10\right)\)
\(=-6+\left(-20\right)+\left(-20\right)+\left(-10\right)=-6-20-20-10=-56\)