Useful simple maths collection for games development

Here, I've collected the useful mathematics calculation to be used in everyday game development. Keep me posted if you have other useful daily mathematics calculate useful in game.

Calculating percentage from current and maximum value

float percent =(current / maximum) * 100.0f

Calculating value from the current and percentage

float value = (current * percentage) / 100.0f

Calculating Row And Columns in 2D array

     /// Get the row number of the grid cell in a given index  
    public int GetRowFromIndex(int index, int numRows)  
    {  
      int row =  Mathf.FloorToInt((float)index / (float)numColumns); 
      return row;  
    }  
    /// Get the column number of the grid cell in a given index  
    public int GetColumnFromIndex(int index, int numColumns)  
    {  
      int col = index % numColumns;  
      return col;  
    }  
    /// Get the index from the given row and column  
    public int GetIndexFromRowCol(int curRow, int curCol, int numRows, int numColumns)  
    {  
      int index = (curRow * numColumns) + curCol;  
      return index;  
    }