Question

\(\frac{-4}{12}\)+\(\frac{18}{45}\)+\(\frac{-6}{9}\)+\(\frac{-21}{35}\)+\(\frac{6}{30}\)

Tính nhanh.

Answer 1

-4/12 + 18/45 - 6/9 - 21/35 + 6/30

= -1/3 + 2/5 - 2/3 - 3/5 + 1/5

= (2/5 - 3/5 + 1/5) - (1/3 + 2/3)

= 0 - 1

= -1

Answer 2

\(=-\frac{1}{3}+\frac{2}{5}-\frac{2}{3}-\frac{3}{5}+\frac{1}{5}\)

\(=\left(-\frac{1}{3}-\frac{2}{3}\right)+\left(\frac{2}{5}-\frac{3}{5}+\frac{1}{5}\right)\)

\(=-1+0\)

\(=-1\)

=.= hk tốt!!