( 7/20 + 11/15 - 15/12 ) : ( 11/20 - 26/45 )

= -1/6 : -1/36

= -5/36

\(A=\left(\dfrac{5}{12}.\dfrac{21}{15}\right):\dfrac{1}{4}\)

\(=\dfrac{7}{12}:\dfrac{1}{4}\)

\(=\dfrac{28}{12}=\dfrac{7}{3}\)

\(B=\left(\dfrac{2}{7}:\dfrac{5}{4}\right).\left(\dfrac{5}{8}:2\right)\)

\(=\dfrac{8}{35}.\left(\dfrac{5}{8}:2\right)\)

\(=\dfrac{8}{35}.\dfrac{5}{16}\)

\(=\dfrac{1}{14}\)

\(C=\left(\dfrac{11}{15}.\dfrac{35}{44}\right).\left(\dfrac{1}{7}.\dfrac{4}{13}\right)\)

\(=\dfrac{7}{12}.\left(\dfrac{1}{7}.\dfrac{4}{13}\right)\)

\(=\dfrac{7}{12}.\left(\dfrac{1}{7}.\dfrac{4}{13}\right)\)

\(=\dfrac{7}{12}.\dfrac{4}{91}\)

\(=\dfrac{1}{39}\)

\(D=\left(\dfrac{7}{20}+\dfrac{11}{15}-\dfrac{15}{12}\right):\left(\dfrac{11}{20}-\dfrac{26}{45}\right)\)

\(=\left(\dfrac{13}{12}-\dfrac{15}{12}\right):\left(\dfrac{11}{20}-\dfrac{26}{45}\right)\)

\(=\dfrac{-1}{6}:\left(\dfrac{11}{20}-\dfrac{26}{45}\right)\)

\(=\dfrac{-1}{6}:\dfrac{-1}{36}\)

\(=6\)

bằng 6 nha

\(a,\left(\dfrac{7}{20}+\dfrac{11}{15}-\dfrac{15}{12}\right):\left(\dfrac{11}{20}-\dfrac{26}{45}\right).\)

\(=\left(\dfrac{21}{60}+\dfrac{44}{60}-\dfrac{75}{60}\right):\left(\dfrac{99}{180}-\dfrac{104}{180}\right).\)

\(=\left(\dfrac{65}{60}-\dfrac{75}{60}\right):\left(-\dfrac{5}{180}\right).\)

\(=-\dfrac{10}{60}:\left(-\dfrac{5}{180}\right).\)

\(=-\dfrac{1}{6}:\left(-\dfrac{1}{36}\right).\)

\(=-\dfrac{1}{6}.\left(-36\right).\)

\(=\dfrac{-1.\left(-36\right)}{6}=\dfrac{36}{6}=6.\)

Vậy......

\(b,\dfrac{5-\dfrac{5}{3}+\dfrac{5}{9}-\dfrac{5}{27}}{8-\dfrac{8}{3}+\dfrac{8}{9}-\dfrac{8}{27}}:\dfrac{15-\dfrac{15}{11}+\dfrac{15}{121}}{16-\dfrac{16}{11}+\dfrac{16}{121}}.\)

\(=\dfrac{5\left(1-\dfrac{1}{3}+\dfrac{1}{9}-\dfrac{1}{27}\right)}{8\left(1-\dfrac{1}{3}+\dfrac{1}{9}-\dfrac{1}{27}\right)}:\dfrac{15\left(1-\dfrac{1}{11}+\dfrac{1}{121}\right)}{16\left(1-\dfrac{1}{11}+\dfrac{1}{121}\right)}.\)

\(=\dfrac{5}{8}:\dfrac{15}{16}.\)

\(=\dfrac{5}{8}.\dfrac{16}{15}=\dfrac{5.16}{8.15}=\dfrac{1.2}{1.3}=\dfrac{2}{3}.\)

Vậy......

c, (làm tương tự câu b).

~ Học tốt!!! ~

10:15: it’s a quarter past ten

1. 20:15  it’s a quarter past eight p.m.
2. 07:40  it’s twenty to eight.

3. 14:50: it's fifty past two p.m.

4. 18:23: it's twenty-three past six p.m.

5. 06:17: it's seventeen past six

6. 20:45: it's a quarter to nine p.m.

7. 11:00: it's eleven o'clock

8. 14:55: it's fifty-five past two p.m. / five to three p.m

9. 21:46: it's forty-six past nine p.m.

10. 22:30: it's half past ten p.m.

11. 12:15: it's a quarter past twelve

12. 05:42: it's forty-two past five

13. 16:23: it's twenty-three past four p.m.

14. 10:45: it's ten forty-five

15. 17:08: it's eight past five p.m.

Minh Châu Tiến Đạt thân mến, với bài đọc thời gian này em chỉ cần lưu ý:

- Cách đọc 1: giờ trước, phút sau: số giờ + số phút (+ p.m. hoặc a.m. hoặc in the evening / in the morning)

- Cách đọc 2: phút trước, giờ sau:

Đối với phút thứ 1-30, chúng tôi sử dụng PAST sau phút. Ex: eight past ten (10h08p)

Đối với phút thứ 31-59, chúng ta sử dụng TO sau phút. Ex: eight to ten (9h52p)

✽ O'clock được sử dụng với giờ đúng, KHÔNG có phút. Ex: 10 o'clock (10:00) -

✽ 12:00 Đối với 12h, có bốn cách diễn đạt bằng tiếng Anh:

 midday = noon / midnight / twelve o'clock

✽15 = a quarter (1/4 của 60 phút / 1 giờ = 15 phút)

✽ a.m. (am) được dùng cho buổi sáng và p.m. (pm) cho buổi chiều và đêm.

Phản hồi đến em.