Question

Tính nhanh 

1/7 . 5/9 + 5/9 . 1/7 +5/9 . 3/7

Ai nhanh mk tick

Answer 1

\(\frac{1}{7}.\frac{5}{9}+\frac{5}{9}.\frac{1}{7}+\frac{5}{9}.\frac{3}{7}\)

\(=\frac{5}{9}.\left(\frac{1}{7}+\frac{1}{7}+\frac{3}{7}\right)\)

\(=\frac{5}{9}.\frac{5}{7}=\frac{25}{63}\)

học vui!

Answer 2

= 5/9 . ( 1/7 + 1/7 + 3/7 )

= 5/9 . 5/7

= 25/63

Tk nha !!

Answer 3

Đặt thừa số chung là 5/9 là xong

Answer 4

=5/9+(1/7+1/7+3/7)

= 5/9+5/7

= 35/63+45/63

= 80/63