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\(a,\dfrac{5}{9}\times\dfrac{5}{2}+\dfrac{4}{9}\times\dfrac{5}{2}=\dfrac{5}{2}\times\left(\dfrac{5}{9}+\dfrac{4}{9}\right)=\dfrac{5}{2}\times1=\dfrac{5}{2}\)
\(12\times\dfrac{3}{4}-\dfrac{3}{4}\times\dfrac{12}{7}=\dfrac{3}{4}\times\left(12-\dfrac{12}{7}\right)=\dfrac{3}{4}\times\dfrac{72}{7}=\dfrac{54}{7}\)
\(\dfrac{12}{7}\) \(\times\) \(\dfrac{3}{4}\) - \(\dfrac{3}{4}\) \(\times\) \(\dfrac{12}{7}\)
= \(\dfrac{9}{7}\) - \(\dfrac{9}{7}\)
= 0
7/9 x 5/16 : 5/9 x4/7
=7/9 x 5/16 x9/5 x 4/7
=7/9 x 45/80 x 4/7
=7/9 x 9/16 x 4/7
=7 x 9 x 4 /9 x 16 x 7
=1/4
\(\dfrac{7}{15}+\dfrac{4}{5}=\dfrac{7}{15}+\dfrac{12}{15}=\dfrac{19}{15}\)
\(\dfrac{2}{3}-\dfrac{3}{8}=\dfrac{16}{24}-\dfrac{9}{24}=\dfrac{7}{24}\)
\(\dfrac{4}{7}.\dfrac{21}{16}:\dfrac{5}{8}=\dfrac{4}{7}.\dfrac{21}{16}.\dfrac{8}{5}=\dfrac{4.3.7.4.2}{7.4.4.5}=\dfrac{6}{5}\)
2/3 * 10/21 * 3/2 = (2/3 * 3/2) * 10/21 = 1 * 10/21 = 10/21
22/5 * 12 * 5/12 = 22/5 * (12 * 5/12) = 22/5 * 5 =22
7/2 * 28/81 * 2/7= (7/2 * 2/7) * 28/81 = 1 * 28/81 =28/81
5/17 * 21/4 * 47/15 * 0 = 0
~Study well~
#Seok_Jin#
= 17/7 + 4/7 - 2/5 + 3/5
= 21/7 - 5/5
= 3 - 1
= 2