`-3/3*15/13-3/7*11/13-3/7`
`-1*15/13-3/7*11/13-3/7`
`=-3/7:3/7*15/13-3/7*11/13-3/7`
`=-3/7*35/13-3/7*11/13-3/7`
`=-(3/7*35/13+3/7*11/13+3/7)`
`=-3/7(35/13+11/13+1)`
`=-3/7*59/13`
`=-177/91`
Cho A =5/4.3+14/3/23+16/23.13+7/13.46
B= 3/2.7+15/7.11+13/11.25+11/35.23. Tìm tỉ số A và B
3/4-3/5+3/7+3/11 / 13/4-13/5+13/7+13/11
1/3-3/5+5/7-7/9+9/11-11/13+13/15+11/13-9/11+7/9-5/7+3/5-1/3
3/7(7/13-3/7) - 7/13( -3/7+26/49)
3/7(7/13-3/7) - 7/13( -3/7+26/49)
Xét xem tổng (hiệu) sau là số nguyên tố hay hợp số? Vì sao?
a) 3. 4. 5 + 6. 7 b) 7. 9. 11. 13 – 2. 3. 4. 7
c) 3. 5. 7 + 11. 13. 17 d) 16 354 + 67 541
e) 1. 3. 5. 7. … . 13 + 20 f) 147. 247. 347 – 13
h) 1. 3. 5. 7. … . 13 + 20
tính nhanh: 1/3-3/5+5/7-7/9+9/11-11/13+13/15+11/13-9/11+7/9-5/7+3/5-1/3
Sắp xếp các phân số sau \(\dfrac{-5}{3};\dfrac{13}{2};\dfrac{7}{-3};1\) theo thứ tự giảm dần:
A. \(\dfrac{13}{2};1;\dfrac{7}{-3};\dfrac{-5}{3}\)
B. \(\dfrac{13}{2};1;\dfrac{-5}{3};\dfrac{7}{-3}\)
C. \(\dfrac{7}{-3};\dfrac{-5}{3};1;\dfrac{13}{2};\)
D. \(\dfrac{7}{-3};\dfrac{-5}{3};\dfrac{13}{2};1\)
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
