p5 Maths

和樓上網友的答案不同，分別是第1題及第7題。
1. 5/7*5/12÷1 1/14
= 5/7 * 5/12 / 15/14
= 5/7 * 5/12 * 14/15
= 5/6 * 1/3
= 5/18

2. 9/10*(5 5/12-1/4)
= 9/10 * (65/12 - 3/12)
= 9/10 * 62/12
= 3/5 * 31/4
= 93/20
= 4 13/20

3. 1 1/3÷1 7/9÷5/6
= 4/3 / 16/9 / 5/6
= 4/3 * 9/16 * 6/5
= 3/2* 3/5
= 9/10

4. 1 5/7+2 2/3*3 9/14
= 12/7 + 8/3 * 51/14
= 12/7 + 4 * 17/7
= 12/7 + 68/7
= 80/7
= 11 3/7

5. 1 1/4-7/16÷3/4
= 5/4 – 7/16 * 4/3
= 5/4 – 7/4 * 1/3
= 5/4 – 7/12
= 15/12 – 7/12
= 8/12
= 2/3

6. (2 5/6-1 2/3)÷1 1/6
= (17/6 – 5/3) / 7/6
= (17/6 – 10/6) * 6/7
= 7/6 * 6/7
= 1

7. 2 1/2÷(2 1/3-5/6)*3/4
= 5/2 / (7/3 – 5/6) * 3/4
= 5/2 / (14/6-5/6)*3/4
= 5/2 / (9/6 * 3/4)
= 5/2 / (27/24)
= 5/2 * 24/27
= 5 * 12/27
= 60/27
= 2 6/27
= 2 2/9

8. 17 1/2÷1 2/5+ 43/10
= 35/2 / 7/5 + 43/10
= 35/2 * 5/7 + 43/10
= 5/2 * 5 + 43/10
= 25/2 + 43/10
= 125/10 + 43/10
= 168/10
= 16 8/10
= 16 5/4

9. 600-3/10
= 6000/10 – 3/10
= 5997/10
= 599 7/10

10. 28÷6
= 28/6
= 14/3
= 4 2/3

11. 12÷2 1/2
= 12 / 5/2
= 12 * 2/5
= 24/5
= 4 4/5

5/7*5/12÷1 1/14
=5/7*5/12*14/15
=35/18
=1 17/18

9/10*(5 5/12-1/4)
= 9/10*(65/12-3/12)
=93/20
= 4 13/20

1 1/3÷1 7/9÷5/6
=4/3*9/16*6/5
=9/10

1 5/7+2 2/3*3 9/14
=12/7+8/3*51/7
=80/7
=11 3/7

1 1/4-7/16÷3/4
=5/4-7/16*4/3
=5/4-7/12
=15/12-7/12
=2/3

(2 5/6-1 2/3)÷1 1/6
=(17/6-5/3)*6/7
=(17/6-10/6)*6/7
=7/6*6/7
=1

2 1/2÷(2 1/3-5/6)*3/4
=3/2 / (7/3-5/6)*3/4
=3/2 / (14/6-5/6)*3/4
=3/2*6/9*3/4
=3/4

17 1/2÷1 2/5+4 3/10
=35/2*5/7+43/10
=25/2+43/10
=125/10+43/10
=168/10
=16 4/5

600-3/10
=5997/10

28÷6
=4 2/3

12÷2 1/2
=12*2/5
=4 4/5