Question

So sánh các phân số sau :

a) \(\dfrac{3}{4}\)và \(\dfrac{333}{444}\)

b) \(\dfrac{-1212}{2323}\)và \(\dfrac{-12}{23}\)

c) \(\dfrac{17}{19}\)và \(\dfrac{1717}{1919}\)

Answer 1

a)\(\dfrac{3}{4}\)và \(\dfrac{333}{444}\)

Vì \(\dfrac{333}{444}=\dfrac{3}{4}\)

Mà \(\dfrac{3}{4}=\dfrac{3}{4}\)=>\(\dfrac{3}{4}=\dfrac{333}{444}\)

Answer 2

mấy ý sau làm tương tự bạn nhé

Answer 3

\(a.\)

\(\dfrac{3}{4}=\dfrac{3.111}{4.111}=\dfrac{333}{444}\)

Vậy \(\dfrac{3}{4}=\dfrac{333}{444}\)

\(b.\)

\(-\dfrac{12}{23}=\dfrac{-12.101}{23.101}=-\dfrac{1212}{2323}\)

Vậy \(-\dfrac{12}{23}=-\dfrac{1212}{2323}\)

\(c.\)

\(\dfrac{17}{19}=\dfrac{17.101}{19.101}=\dfrac{1717}{1919}\)

Vậy \(\dfrac{17}{19}=\dfrac{1717}{1919}\)

Answer 4

a)ta có\(\dfrac{3}{4}\) và \(\dfrac{333}{444}\)

\(\dfrac{3}{4}\)=\(\dfrac{3.111}{4.111}\)=\(\dfrac{333}{444}\)

=>\(\dfrac{3}{4}\)=\(\dfrac{333}{444}\)

vậy hai phân số này bằng nhau

b)\(\dfrac{-1212}{2323}\)và \(\dfrac{-12}{23}\)

\(\dfrac{-1212}{2323}\)=\(\dfrac{-1212:101}{2323:101}\)=\(\dfrac{-12}{23}\)

vậy hai phân số này bằng nhau

c)\(\dfrac{17}{19}\)và\(\dfrac{1717}{1919}\)

\(\dfrac{17}{19}\)=\(\dfrac{17.101}{19.101}\)=\(\dfrac{1717}{1919}\)

vậy hai phân số này bằng nhau

Bài chỉ có vậy thôi. Xem rồi tham khảo nhé!

Answer 5

a) Xét \(\dfrac{333}{444}=\dfrac{333:111}{444:111}=\dfrac{3}{4}\)

Vì \(\dfrac{3}{4}=\dfrac{3}{4}\) nên \(\dfrac{333}{444}=\dfrac{3}{4}\)

b) Xét \(\dfrac{-1212}{2323}=\dfrac{\left(-1212\right):101}{2323:101}=\dfrac{-12}{23}\)

Vì \(\dfrac{-12}{23}=\dfrac{-12}{23}\) nên \(\dfrac{-1212}{2323}=\dfrac{-12}{23}\)

c) Xét \(\dfrac{1717}{1919}=\dfrac{1717:101}{1919:101}=\dfrac{17}{19}\)

Vì \(\dfrac{17}{19}=\dfrac{17}{19}\) nên \(\dfrac{1717}{1919}=\dfrac{17}{19}\)

Answer 6

(Hoặc là làm ngược lại)

a) Xét \(\dfrac{3}{4}=\dfrac{3.111}{4.111}=\dfrac{333}{444}\)

Vì \(\dfrac{333}{444}=\dfrac{333}{444}\) nên \(\dfrac{3}{4}=\dfrac{333}{444}\).

b) Xét \(\dfrac{-12}{23}=\dfrac{\left(-12\right).101}{23.101}=\dfrac{-1212}{2323}\)

Vì \(\dfrac{-1212}{2323}=\dfrac{-1212}{2323}\) nên \(\dfrac{-12}{23}=\dfrac{-1212}{2323}\)

c) Xét \(\dfrac{17}{19}=\dfrac{17.101}{19.101}=\dfrac{1717}{1919}\)

Vì \(\dfrac{1717}{1919}=\dfrac{1717}{1919}\) nên \(\dfrac{17}{19}=\dfrac{1717}{1919}\)

Answer 7

a) \(\dfrac{3}{4}\) và \(\dfrac{333}{444}\)

\(\dfrac{333}{444}\) = \(\dfrac{333:111}{444:111}\) = \(\dfrac{3}{4}\)

=> \(\dfrac{333}{444}\) = \(\dfrac{3}{4}\)

b) \(\dfrac{-1212}{2323}\) và \(\dfrac{-12}{23}\)

\(\dfrac{-1212}{2323}\) = \(\dfrac{-1212:101}{2323:101}\) = \(\dfrac{-12}{23}\)

=> \(\dfrac{-1212}{2323}\) = \(\dfrac{-12}{23}\)

c) \(\dfrac{17}{19}\) và \(\dfrac{1717}{1919}\)

\(\dfrac{1717}{1919}\) = \(\dfrac{1717:101}{1919:101}\) = \(\dfrac{17}{19}\)

=> \(\dfrac{1717}{1919}\) = \(\dfrac{17}{19}\)

Answer 8

a. Ta có: \(\dfrac{333}{444}=\dfrac{333:111}{444:111}=\dfrac{3}{4}\)

Vậy: 333/444 = 3/4

b. Ta có: \(\dfrac{-1212}{2323}=\dfrac{-1212:101}{2323:101}\dfrac{-12}{23}\)

Vậy: -1212/2323 = -12/23

c. Ta có: \(\dfrac{17}{19}=\dfrac{17\cdot101}{19\cdot101}=\dfrac{1717}{1919}\)

Vậy: 17/19 = 1717/1919