a)rút gọn 3 vs 15

14vs21

=1.5

b)=8

a)\(\frac{3.21}{14.15}=\frac{1.3}{2.5}=\frac{3}{10}\)

b)\(\frac{49+7.49}{49}=\frac{49.\left(1+7\right)}{49}=\frac{8}{1}=8\)

a)\(\frac{3.21}{14.15}=\frac{1.3}{2.5}=\frac{3}{10}\)

b)\(\frac{49+7.49}{49}=\frac{49.\left(1+7\right)}{49}=1.8=8\)

\(\frac{17.5-17}{3-20}=\frac{68}{-17}\)

\(\frac{49+7.49}{49}=\frac{8.49}{49}=8\)

\(\frac{3.21}{14.15}=\frac{1.3.7.3}{2.7.3.5}=\frac{1.3}{2.5}=\frac{3}{10}\)

a) $\frac{4.7}{9.32}=\frac{4.7}{\mathrm{9.4.8}}=\frac{7}{9.8}=\frac{7}{72}$

b) $\frac{3.21}{14.15}=\frac{\mathrm{3.3.7}}{\mathrm{2.7.3.5}}=\frac{3}{2.5}=\frac{3}{10}$

c) $\frac{\mathrm{2.5.13}}{26.35}=\frac{\mathrm{2.5.13}}{\mathrm{2.13.5.7}}=\frac{1}{7}$

d) $\frac{9.6–9.3}{18}=\frac{9.(6–3)}{9.2}=\frac{6–3}{2}=\frac{3}{2}$

e) $\frac{17.5–17}{3–20}=\frac{17.(5–1)}{–17}=\frac{5–1}{–1}=–4$

f) $\frac{49+7.49}{49}=\frac{49.(1+7)}{49}=1+7=8$

a) \(\dfrac{4.7}{9.32}=\dfrac{4.7}{9.4.8}=\dfrac{7}{72}\)

b) \(\dfrac{3.21}{14.15}=\dfrac{3.3.7}{2.7.3.5}=\dfrac{3}{10}\)

c) \(\dfrac{2.5.13}{26.35}=\dfrac{2.5.13}{2.13.5.7}=\dfrac{1}{7}\)

d) \(\dfrac{9.6-9.3}{18}=\dfrac{9\left(6-3\right)}{9.2}=\dfrac{3}{2}\)

e) \(\dfrac{17.5-17}{3-20}=\dfrac{17\left(5-1\right)}{-17}=\dfrac{5-1}{-1}=-4\)

f) \(\dfrac{49+7.49}{49}=\dfrac{49\left(1+7\right)}{49}=8\)

phân số của bạn là như vậy phải không?

\(\frac{49+7\cdot49}{49}\)

\(49+7\cdot\frac{49}{49}\)\(=49+7+1\)

**** !

\(\frac{4\cdot7}{9\cdot32}=\frac{4\cdot7}{9\cdot8\cdot4}=\frac{7}{8\cdot9}=\frac{7}{72}\)

\(\frac{2\cdot5\cdot13}{26\cdot35}=\frac{2\cdot5\cdot13}{2\cdot13\cdot7\cdot5}=\frac{1}{7}\)

\(\frac{3\cdot21}{14\cdot15}=\frac{3\cdot3\cdot7}{2\cdot7\cdot3\cdot5}=\frac{3}{2\cdot5}=\frac{3}{10}\)

\(\frac{9\cdot6-9\cdot3}{18}=\frac{9\cdot\left(6-3\right)}{9\cdot2}=\frac{9\cdot3}{9\cdot2}=\frac{3}{2}\)

\(\frac{17\cdot5-17}{3-20}=\frac{17\cdot\left(5-1\right)}{-17}=\frac{17\cdot4}{17\cdot\left(-1\right)}=\frac{4}{-1}=-4\)

\(45dm^2=0,45m^2\)

\(300cm^2=0,03m^2\)

\(57500mm^2=0,0575m^2\)

Rút gọn A và B

\(A=\frac{3.21}{7.15}=\frac{63}{105}=\frac{3}{5}\)

\(B=\frac{49-7.49}{49.9}=\frac{-294}{441}=\frac{-2}{3}\)

Quy đồng 2 phân số có mẫu số chung :

\(\frac{3}{5}=\frac{3.3}{5.3}=\frac{9}{15}\)

\(\frac{-2}{3}=\frac{-2.5}{3.5}=\frac{-10}{15}\)

Vậy tổng của A và B là : \(\frac{9}{15}+\frac{-10}{15}=\frac{9+\left(-10\right)}{15}=\frac{-1}{15}\)

A= 3.21/7.15

A= 3.3.7/7.3.5

A= 3/5

B= 49-7.49/49.9

B= 49.(7-1)/49.9

B= 49.6/49.9

B= 6/9

B= 2/3

Ta có: A= 3/5

B= 2/3

=> A+B= 3/5 + 2/3

= 9/15 + 10/15

= 19/15

Vậy A +B= 19/15

Hơi khó nhìn

Thông cảm nhé !