Simple and best solution with logic mentioned. Upvote if you understood:)
Intuition\n Describe your first thoughts on how to solve this problem. \n\n# Approach\n Describe your approach to solving the problem. \n\n# Complexity\n- Time 
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```\nclass Solution {\npublic:\n    int minimumSum(int num) {\n        vector<int> ans(4);\n        for(int i=3;i>=0;i--)\n        {\n            ans[i]=num%10;\n            num/=10;\n        }\n\n        /* to make min sum, the 1st elements of both num1 and num2 should be either arr[0] or arr[1] after sorting the arr, or we can say the the min elements. */\n        sort(ans.begin(),ans.end());\n\n        int sum1=(ans[0]*10 + ans[2]);\n        int sum2=(ans[1]*10 + ans[3]);\n\n        return sum1+sum2;\n    }\n};\n```
['C++']