Tính nhẩm.
13 – 5 13 – 4 13 – 6
13 – 8 13 – 7 13 – 9
Tính nhẩm:
13 − 9 = ..... 13 − 8 = .....
13 − 5 = ..... 13 − 6 = .....
13 − 4 = ..... 13 − 7 = .....
13 − 3 − 2 = ..... 13 − 5 = .....
Phương pháp giải:
Trừ nhẩm các số rồi điền kết quả thích hợp vào chỗ trống.
Lời giải chi tiết:
13 − 9 = 4 13 − 8 = 5
13 − 5 = 8 13 − 6 = 7
13 − 4 = 9 13 − 7 = 6
13 − 3 − 2 = 8 13 − 5 = 8
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
Tìm x , biết:
1) 476 : x = 28
2) x : 26 = 39
3) 6.x - 5 = 613
4) x - 36 : 18 = 12
5) 9.x - 13 = 671
6) x : 7 - 13 =57
7) x + 13 = 14
8) x - 19 = 21
9 ) x : 13 = 6
10) 74 - x = 13
1, 476 : x =28
x=476 : 28
x=17
Vậy x= 17
,2, x : 26 = 39
x=39 . 26
x=1014
Vậy x= 1014
Thôi nhiều quá mình không trả lời được
~Thôi chúc bạn học giỏi~
1)476:x=28
x=476:28
x=17
2)x:26=39
x=39x26
x=1014
476 : x = 68
x. = 476 : 68
x. = 7
Tính nhẩm:
a)
7 + 5 = ..... 5 + 7 = .....
4 + 9 = ..... 9 + 4 = .....
8 + 7 = ..... 7 + 8 = .....
2 + 9 = ..... 9 + 2 = .....
b)
16 − 8 = ..... 14 − 7 = .....
11 − 9 = ..... 17 − 9 = .....
12 − 5 = ..... 16 − 9 = .....
13 − 6 = ..... 15 − 8 = .....
Phương pháp giải:
Tính nhẩm rồi điền kết quả vào chỗ trống.
Lời giải chi tiết:
a)
7 + 5 = 12 5 + 7 = 12
4 + 9 = 13 9 + 4 = 13
8 + 7 = 15 7 + 8 = 15
2 + 9 = 11 9 + 2 = 11
b)
16 − 8 = 8 14 − 7 = 7
11 − 9 = 2 17 − 9 = 8
12 − 5 = 7 16 − 9 = 7
13 − 6 = 7 15 − 8 = 7
7+5=17 5+7=17
4+9=13 9+4=13
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
So sánh 10^2000+5/10^2001-8 và 10^2000+6/10^2001-7
Tính 1+13^4+13^8+...+13^96+13^100/1+13^2+13^4+...+13^98+13^100+13^102
Tính A=2/5.7+5/7.12+9/19.28+11/28.39+1/39.40
Tính nhanh
A)-3/7+5/13-4/7+8/13
B)-5/14-2/-14+1/8+1/8
C)-5/13-(3/5+3/13-4/10)
D)[1/8-9/7+4/6-12/7-1/2)+5/9]
a, \(\frac{-3}{7}+\frac{5}{13}-\frac{4}{7}+\frac{8}{13}\)
\(=\frac{-3}{7}-\frac{4}{7}+\frac{5}{13}+\frac{8}{13}\)
\(=-\frac{7}{7}+\frac{13}{13}=-1+1=0\)
b, \(\frac{-5}{14}-\frac{2}{-14}+\frac{1}{8}+\frac{1}{8}\)
\(=\frac{-5}{14}+\frac{2}{14}+\frac{1}{8}+\frac{1}{8}\)
\(=-\frac{3}{14}+\frac{1}{4}=\frac{1}{28}\)
c,\(-\frac{5}{13}-\left(\frac{3}{5}+\frac{3}{13}-\frac{4}{10}\right)\)
\(=-\frac{5}{13}-\frac{3}{13}-\frac{3}{5}+\frac{4}{10}\)
\(=-\frac{8}{13}-\frac{3}{5}+\frac{4}{10}=-\frac{79}{65}+\frac{4}{10}=-\frac{53}{65}\)
d, \(\left[\left(\frac{1}{8}-\frac{9}{7}+\frac{4}{6}-\frac{12}{7}-\frac{1}{2}\right)+\frac{5}{9}\right]\)
\(=\left[\left(\frac{1}{8}-\frac{9}{7}+\frac{2}{3}-\frac{12}{7}-\frac{1}{2}\right)+\frac{5}{9}\right]\)
\(=\left[\left(\frac{1}{8}-\frac{1}{2}-\frac{9}{7}-\frac{12}{7}+\frac{2}{3}\right)+\frac{5}{9}\right]\)
\(=-\frac{65}{24}+\frac{5}{9}=-2\frac{11}{72}\)
Tính nhẩm:
14 − 9 = ..... | 16 − 7 = ..... | 12 − 8 = ..... | 6 + 9 = ..... |
8 + 8 = ..... | 11 − 5 = ..... | 13 − 6 = ..... | 18 − 9 = ..... |
14 − 6 = ..... | 17 − 8 = ..... | 12 − 5 = ..... | 3 + 9 = ..... |
9 + 4 = ..... | 11 − 9 = ..... | 3 + 8 = ..... | 16 − 8 = ..... |
Phương pháp giải:
Tính nhẩm các số rồi điền kết quả vào chỗ trống.
Lời giải chi tiết:
14 − 9 = 5 | 16 − 7 = 9 | 12 − 8 = 4 | 6 + 9 = 15 |
8 + 8 = 16 | 11 − 5 = 6 | 13 − 6 = 7 | 18 − 9 = 9 |
14 − 6 = 8 | 17 − 8 = 9 | 12 − 5 = 7 | 3 + 9 = 12 |
9 + 4 = 13 | 11 − 9 = 2 | 3 + 8 = 11 | 16 − 8 = 8 |
Tính nhẩm:
14 − 9 = ..... | 16 − 7 = ..... | 12 − 8 = ..... | 6 + 9 = ..... |
8 + 8 = ..... | 11 − 5 = ..... | 13 − 6 = ..... | 18 − 9 = ..... |
14 − 6 = ..... | 17 − 8 = ..... | 12 − 5 = ..... | 3 + 9 = ..... |
9 + 4 = ..... | 11 − 9 = ..... | 3 + 8 = ..... | 16 − 8 = ..... |
Thực hiện phép tính:
1,-4/7 + 2/3x -9/14
2,17/13 - ( 4/13 - 11 )
3, 8 2/7 - ( 3 4/9 + 4 2/7 )
5, ( 2/3 - 1 1/2): 4/3 + 1/2
6, -5/13 + 2/5 + -8/13 + 3/5 - 3/7
7, 6/5 x 3/7 + 6/5 : 7/10 + 6/5
\(1,-\dfrac{4}{7}+\dfrac{2}{3}\times\dfrac{-9}{14}\)
\(=\dfrac{-4}{7}+\dfrac{-18}{42}\)
\(=\dfrac{-4\times6}{7\times6}+\dfrac{-18}{42}\)
\(=\dfrac{-20}{42}+\dfrac{-18}{42}\)
\(=-\dfrac{38}{42}\)
\(=-\dfrac{19}{21}\)
\(2,\dfrac{17}{13}-\left(\dfrac{4}{13}-11\right)\)
\(=\dfrac{17}{13}-\dfrac{4}{13}+11\)
\(=\dfrac{13}{13}+11\)
\(=1+11\)
\(=12\)
\(3,8\dfrac{2}{7}-\left(3\dfrac{4}{9}+4\dfrac{2}{7}\right)\)
\(=\dfrac{58}{7}-\left(\dfrac{31}{9}+\dfrac{30}{7}\right)\)
\(=\dfrac{58}{7}-\dfrac{31}{9}-\dfrac{30}{7}\)
\(=\dfrac{58}{7}-\dfrac{30}{7}-\dfrac{31}{9}\)
\(=\dfrac{28}{7}-\dfrac{31}{9}\)
\(=\dfrac{28\times9}{7\times9}-\dfrac{31\times7}{9\times7}\)
\(=\dfrac{252}{63}-\dfrac{217}{63}\)
\(=\dfrac{35}{63}\)
\(=\dfrac{5}{9}\)
\(5,\left(\dfrac{2}{3}-1\dfrac{1}{2}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\left(\dfrac{2}{3}-\dfrac{3}{2}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\left(\dfrac{2\times2}{3\times2}-\dfrac{3\times3}{2\times3}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\left(\dfrac{4}{6}-\dfrac{9}{6}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\dfrac{-5}{6}:\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\dfrac{-5}{6}\times\dfrac{3}{4}+\dfrac{1}{2}\)
\(=\dfrac{-15}{24}+\dfrac{1}{2}\)
\(=\dfrac{-15}{24}+\dfrac{1\times12}{2\times12}\)
\(=\dfrac{-15}{24}+\dfrac{12}{24}\)
\(=\dfrac{-3}{24}\)
\(=-\dfrac{1}{8}\)
\(6,\dfrac{-5}{13}+\dfrac{2}{5}+\dfrac{-8}{13}+\dfrac{3}{5}-\dfrac{3}{7}\)
\(=\left(\dfrac{-5}{13}+\dfrac{-8}{13}\right)+\left(\dfrac{2}{5}+\dfrac{3}{5}\right)-\dfrac{3}{7}\)
\(=\dfrac{-13}{13}+\dfrac{5}{5}-\dfrac{3}{7}\)
\(=-1+1-\dfrac{3}{7}\)
\(=-\dfrac{3}{7}\)
\(7,\dfrac{6}{5}\times\dfrac{3}{7}+\dfrac{6}{5}:\dfrac{7}{10}+\dfrac{6}{5}\)
\(=\dfrac{6}{5}\times\dfrac{3}{7}+\dfrac{6}{5}\times\dfrac{10}{7}+\dfrac{6}{5}\)
\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+1\right)\)
\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+\dfrac{1\times7}{1\times7}\right)\)
\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+\dfrac{7}{7}\right)\)
\(=\dfrac{6}{5}\times\dfrac{20}{7}\)
\(=\dfrac{120}{35}\)
\(=\dfrac{24}{7}\)
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