2/5+4/15= 2/3+3/10= 5/6-3/5= (4/7+2/5)-1/3=

6/15+4/15=10/15 = 1/3

20/30+9/30=29/30

25/30-18/30= 7/30

20/35+14/35-1/3
34/35-1/3
102/105-35/105
67/105

A.[tex] \frac{2}{5} + \frac{4}{15} = \frac{6}{15} + \frac{4}{15} = \frac{10 : 5}{15:5} = \frac{2}{3} [/tex]
B.[tex] \frac{2}{3}+ \frac{3}{10}= \frac{20}{30} + \frac{9}{30} = \frac{29}{30} [/tex]
C.[tex] \frac{5}{6}- \frac{3}{5} = \frac{25}{30}- \frac{18}{30} = \frac{7}{30}[/tex]
D. Mencari 4/7 + 2/5 terlebih dahulu......
    [tex] \frac{4}{7}+ \frac{2}{5}= \frac{20}{35}+ \frac{14}{35} = \frac{34}{35} [/tex]
     Lalu Operasikan 34/35 - 1/3........
      [tex] \frac{34}{35}- \frac{1}{3} = \frac{102}{105}- \frac{35}{105} = \frac{67}{105} [/tex]