Question

Tính bằng cách thuận tiện .  3×7/10+7/10×5+2×14/20

Answer 1

3 x 7/10 + 7/10 x 5 + 2 x 14/20

=3x7/10+7/10x5+2x7/10

=7/10x(3+5+2)

=7/10x10

=7

Answer 2

ta có

\(3\cdot\frac{7}{10}+\frac{7}{10}\cdot5+2\cdot\frac{14}{20}\)

\(=3\cdot\frac{7}{10}+\frac{7}{10}\cdot5+2\cdot\frac{7}{10}\)

\(=\frac{7}{10}\cdot\left(3+5+2\right)\)

\(=\frac{7}{10}\cdot10\)

\(=\frac{70}{10}=7\)

chúc bạn hok tốt!

Answer 3

   3x7/10+7/10x5+2x14/20

=3x7/10+7/10x5+2x7/10

=7/10x(3+5+2)

=7/10x     10

=70/10

=7