` 1/3 - 3/4 -(-3/5) + 1/72 - 2/9 - 1/36 + 1/15`
`= 1/3 - 3/4 + 3/5 + 1/72 - 2/9 - 1/36 + 1/15`
` = ( 1/3 + 3/5 + 1/15) - ( 3/4 + 1/36 - 2/9) + 1/72`
` = ( 5/15 + 9/15 + 1/15) - ( 27/36 + 1/36 - 8/36) + 1/72`
` = 15/15 - 36/36 + 1/72`
` = 1 - 1 + 1/72`
` = 0 + 1/72`
` = 1/72`
\(=\left(\dfrac{1}{3}+\dfrac{3}{5}+\dfrac{1}{15}\right)+\left(-\dfrac{3}{4}-\dfrac{1}{36}+\dfrac{1}{72}-\dfrac{2}{9}\right)\)
\(=\left(\dfrac{5}{15}+\dfrac{9}{15}+\dfrac{1}{15}\right)+\left(-\dfrac{54}{72}-\dfrac{2}{72}+\dfrac{1}{72}-\dfrac{16}{72}\right)\)
\(=\dfrac{15}{15}-\dfrac{71}{72}\)
\(=\dfrac{72}{72}-\dfrac{71}{72}=\dfrac{1}{72}\)
\(=\left(-\dfrac{2}{9}-\dfrac{1}{36}-\dfrac{3}{4}\right)+\left(\dfrac{1}{3}+\dfrac{3}{5}+\dfrac{1}{15}\right)+\dfrac{1}{72}\)
=1/72
1/3 - 3/4 - -3/5 + 1/72 - 2/9 -1/36 + 1/15
= (20/60 - 45/60 - -36/60) + (1/72 - 16/72 - 2/72) + 1/15
= 11/60 + -17/72 + 1/15
= 1/4 + -17/72
= -1/72
