First of all we group like terms together:
⅔m-⅓m+m + ⅗n-⁷⁄₁₀n-½n - r+½r+¾r
Now work out how many m, n and r there are.
m: (⅔-⅓+1)m=⁴⁄₃m
n: (⅗-⁷⁄₁₀-½)n is (⁶⁄₁₀-⁷⁄₁₀-⁵⁄₁₀)n=-⁶⁄₁₀n=-⅗n
r: (-1+½+¾)r=¼r
Now add these together to get the answer: ⁴⁄₃m-⅗n+¼r