tính nhanh
2:28x7
=
=
=
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
=\(\dfrac{2}{3}\times\left(\dfrac{4}{9}+\dfrac{5}{9}\right)=\dfrac{2}{3}\times\dfrac{9}{9}=\dfrac{2}{3}\)
\(=\dfrac{2}{3}\times\left(\dfrac{4}{9}+\dfrac{5}{9}\right)\\ =\dfrac{2}{3}\times1=\dfrac{2}{3}\)
\(\dfrac{2}{9}+\dfrac{3}{7}+\dfrac{15}{13}+\dfrac{4}{7}-\dfrac{2}{13}+\dfrac{7}{9}\)
\(=\left(\dfrac{2}{9}+\dfrac{7}{9}\right)+\left(\dfrac{3}{7}+\dfrac{4}{7}\right)+\left(\dfrac{15}{13}-\dfrac{2}{13}\right)\)
\(=\dfrac{9}{9}+\dfrac{7}{7}+\dfrac{13}{13}=1+1+1=3\)
14,5 x 2,7 + 2,7 x 5,5 - 2,7 x 2 x 5.
= 2,7 x 14,5 + 2,7 x 5,5 - 2,7 x 10
= 2,7 x ( 14,5 + 5,5 - 10 )
= 2,7 x 10
= 27
\(a;\frac{3}{7}+\frac{2}{3}=\frac{9}{21}+\frac{14}{21}=\frac{23}{21}\)
\(b;\frac{8}{7}-\frac{12}{28}\times\frac{7}{3}=\frac{8}{7}-\frac{3}{7}\times\frac{7}{3}=\frac{8}{7}-1=\frac{8}{7}-\frac{7}{7}=\frac{1}{7}\)
\(c;\frac{5}{6}\times3=\frac{15}{6}=\frac{5}{2}\)
\(d;\frac{3}{2}:\frac{7}{15}=\frac{3}{2}\times\frac{15}{7}=\frac{45}{14}\)
a) 3/7+2/3=9/21+14/21=23/21
b) 8/7-12/28*7/3=8/7-1=8/7-7/7-1/7
c) 5/6*3=5/2
d) 3/2:7/15=3/2*15/7=45/14