You can use a number line here.
For example, draw a line 20 units long and mark off the centre as reference point 0.
To the left of the reference point we have equal divisions -10 to -1 and on the right 1 to 10:
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10
Now we take the segment from -4 to 6:
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10
The inequality -4≤x≤6 is this segment, which is ten units long.