Question

tính nhanh

1/5 + 3/7 +4/5 + 11/7

67,52 - 15,39 + 32,48 - 22,13

Answer 1

         \(\frac{1}{5}+\frac{3}{7}+\frac{4}{5}+\frac{11}{7}\)

\(=\left(\frac{1}{5}+\frac{4}{5}\right)+\left(\frac{3}{7}+\frac{11}{7}\right)\)

\(=1+2\)

\(=3\)

\(67,52-15,39+32,48-22,13\)

\(=52,13+10,35\)

\(=62,48\)

Answer 2

1/5 +3/7+4/5+11/7

=  1/5+4/5+3/7+11/7

= 5/5=+ 11/7

= 1 + 11/7

= 18/7