The inside diameter would be the outside diameter minus 2 of the wall thicknesses.
4 9/32 - (2 x 7/32)
Simplify:
4 9/32 - 14/32
Because 14/32 is larger than 9/32 change one of the hole numbers to a fraction: 1 = 32/32
rewrite 4 9/32 as 3 41/32
Now subtract:
3 41/32 - 14/32 = 3 27/32 inside diameter.