Tính nhanh:A=1003.2005-1002/1003+2005.1002.5-5/11+5/7-5/17+5/2004/13/2004-13/17+13/7-13/11+13
a.Tính nhanh:A=1003.2005-1002/1003+2005.1002.5-5/11+5/7-5/17+5/2004/13/2004-13/17+13/7-13/11+13
a) Tính nhanh \(A=\frac{1003\cdot2005-1002}{1003+2005\cdot1002}\cdot\frac{5-\frac{5}{11}+\frac{5}{7}-\frac{5}{17}+\frac{5}{2004}}{\frac{13}{2004}-\frac{13}{17}+\frac{13}{7}-\frac{13}{11}+13}\)
b) So sánh \(2002^{303}\)và \(303^{202}\); \(31^{11}\)và \(17^{14}\)
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
a) -5/11 + ( -6/11 + 1 )
b) -13/17 + ( 13/-21 + -4/17 )
c) -5/12 . 7/-17 . 9/-20
d) 13/17 . 4/-5 + 13/17 . -3/4
e) -5/7 . 2/11 + -5/7 . 9/11 + 5/7
f) -2/5 . (-6) + 3/4 . 4/-10
a: =-5/11-6/11+1=-11/11+1=0
b: =-13/17-13/21-4/17=-1-13/21=-34/21
b: \(=-\dfrac{5}{12}\cdot\dfrac{9}{20}\cdot\dfrac{7}{17}=\dfrac{-21}{272}\)
d: \(=\dfrac{13}{17}\left(-\dfrac{4}{5}-\dfrac{3}{4}\right)=\dfrac{13}{17}\cdot\dfrac{-31}{20}=\dfrac{-403}{340}\)
bài 1 Tính:
a) 5/17 * 8/-7+8/17*-7/3+-7/3*4/17
b) -10/13 + 5/17 - 3/13 + 12/17 - 11/20
giúp tớ vs ạ. Tớ CẢM ƠN
*tớ thêm một câu nữa ạ
c) 5/9 * 7/13 + 5/9 * 9/13 + 3/13 * -5/9
a) 5/17 * 8/-7+8/17*-7/3+-7/3*4/17
-40/119 + 12/17 × -7/3
-40/119 + -28/17 =-236/119
b) -10/13 + 5/17 - 3/13 + 12/17 - 11/20
(5/17+12/17)-(10/13+3/13)-11/20
-11/20
a) 5/17 * 8/-7+8/17*-7/3+-7/3*4/17
-40/119 + 12/17 × -7/3
-40/119 + -28/17 =-236/119
b) -10/13 + 5/17 - 3/13 + 12/17 - 11/20
(5/17+12/17)-(10/13+3/13)-11/20
-11/20
Tính nhanh:
a).31/17+5/13+8/13-14/17 ; b).5/7x22/11+5/7x9/11+5/7
a,\(\frac{31}{17}+\frac{5}{13}+\frac{8}{13}-\frac{14}{17}=\left(\frac{31}{17}-\frac{14}{17}\right)+\left(\frac{5}{13}+\frac{8}{13}\right)=1+1=2\) b,\(\frac{5}{7}.\frac{22}{11}+\frac{5}{7}.\frac{9}{11}+\frac{5}{7}=\frac{5}{7}.\left(\frac{22}{11}+\frac{9}{11}+1\right)=\frac{5}{7}.4=\frac{20}{7}\)
a) \(\frac{31}{17}+\frac{5}{13}+\frac{8}{13}-\frac{14}{17}\)
\(=\left(\frac{31}{17}-\frac{14}{17}\right)+\left(\frac{5}{13}+\frac{8}{13}\right)\)
\(=1+1\)
\(=2\)
b) \(\frac{5}{7}\cdot\frac{22}{11}+\frac{5}{7}\cdot\frac{9}{11}+\frac{5}{7}\)
\(=\frac{5}{7}\cdot\left(\frac{22}{11}+\frac{9}{11}+1\right)\)
\(=\frac{5}{7}\cdot\frac{42}{11}\)
\(=\frac{30}{11}\)
5/9 × 8/17+ 3/17 : 9/7 - 5/9 7/3 × 6/ 11 + 7 / 11 - 5 /13 + 6/ 13
a) -5/12 . 7/-17 . 9/-20
b) 13/17 . 4/-5 + 13/17 . -3/4
c)-5/7 . 2/11 + -5/7 . 9/11 + 5/7
d)-2/5 . (-6) + 3/4 . 4/-10
a: \(=-\dfrac{5}{12}\cdot\dfrac{9}{20}\cdot\dfrac{7}{17}=-\dfrac{21}{272}\)
b: \(=\dfrac{13}{17}\left(-\dfrac{4}{5}-\dfrac{3}{4}\right)=\dfrac{-13}{17}\cdot\dfrac{31}{20}=-\dfrac{403}{340}\)
c: \(=\dfrac{-5}{7}\left(\dfrac{2}{11}+\dfrac{9}{11}\right)+\dfrac{5}{7}=-\dfrac{5}{7}+\dfrac{5}{7}=0\)
d: \(=\dfrac{12}{5}-\dfrac{3}{10}=\dfrac{21}{10}\)
Tính nhẩm:
8 + 9 = ..... | 9 + 8 = ..... | 17 − 8 = ..... | 17 − 9 = ..... |
5 + 7 = ..... | 7 + 5 = ..... | 12 − 5 = ..... | 12 − 7 = ..... |
3 + 8 = ..... | 8 + 3 = ..... | 11 − 3 = ..... | 11 − 8 = ..... |
4 + 9 = ..... | 9 + 4 = ..... | 13 − 4 = ..... | 13 − 9 = ..... |
Phương pháp giải:
Tính nhẩm rồi điền số thích hợp vào chỗ trống.
Lời giải chi tiết:
8 + 9 = 17 | 9 + 8 = 17 | 17 − 8 = 9 | 17 − 9 = 7 |
5 + 7 = 12 | 7 + 5 = 12 | 12 − 5 = 7 | 12 − 7 = 5 |
3 + 8 = 11 | 8 + 3 = 11 | 11 − 3 = 8 | 11 − 8 = 3 |
4 + 9 = 13 | 9 + 4 = 13 | 13 − 4 = 9 | 13 − 9 = 4 |
8+9=17 9+8=17 17-8=9 17-9=8
5+7=12 7+5=12 12-5=7 17-7=5