It seems you're working on a strategy game. Such games usually have units and resources and most of them have an info-bar to show their distribution.

For desktop games, keyboard is used to give commands and directional movements while the mouse is used for trivial and advanced movements, drag and drop, selection, etc. 

In your case, I think it's better to keep things simple and **let the user define the distribution with their keyboard rather than using a range element**. It will be faster and easier for the user and I think gamers will prefer quick assignment of units with their keyboard rather than using sliders or range picker elements. Consider the following mockup:

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The user can simply assign units for each activity. **Unused units can be shown explicitly so that the user does not have to calculate the number of remaining units**. These values can change dynamically (0 to MAX) as the game progresses. This is inspired from the distribution of resources in games like AoE 2, Starcraft 2, etc.

[![enter image description here][1]][1]

Hope this helps!