Question

TÍNH NHANH :

A . 2/3 . 15/17 + 2/3 . 2/17

B . 20/19 : 3/7 - 1/19 : 3/7

CHÚ Ý : DẤU CHẤM LÀ NHÂN

Answer 1

a, \(\frac{2}{3}\).\(\frac{15}{17}\)+\(\frac{2}{3}\).\(\frac{2}{17}\)

= \(\frac{2}{3}\).( \(\frac{15}{17}\)+ \(\frac{2}{17}\))

= \(\frac{2}{3}\). 1

=\(\frac{2}{3}\)

b,\(\frac{20}{19}\):\(\frac{3}{7}\)- \(\frac{1}{19}\): \(\frac{3}{7}\)

= ,\(\frac{20}{19}\).\(\frac{7}{3}\)- \(\frac{1}{19}\).\(\frac{7}{3}\)

= \(\frac{7}{3}\).(\(\frac{20}{19}\)-\(\frac{1}{19}\))

=\(\frac{7}{3}\).1

=\(\frac{7}{3}\)