Inclusion–exclusion

Single − pair + triple … signs alternate.

Try this in Python

def ie3(a, b, c, ab, ac, bc, abc):
    return a + b + c - ab - ac - bc + abc

print(ie3(10, 10, 10, 3, 3, 3, 1))

Key takeaways

• Same universe.
• Bitmask analog.
• Layer tricks.