If 6 times a is increased by 4 the result is the same as the number decrease by 16. find the number.

 
1. You need to first convert the text into math.
Let the mystery number be x.
6 times a number is equivalent to "6x"
increased by 4 is equivalent to "+4"
the result is the same is equivalent to "="
the number decreased by 16 is equivalent to "x-16"

2. Piece it all together, which is 6x +4 = x -16.

3. solve for x to find the mystery number: 
6x + 4 - x = -16
5x + 4 = -16
5x = -12
x = -12/5

This means your myster number is -12/5
Hope this helps!
and May the Force Be With You

-Jabba