Pascal modulo with negative divisor: If A = 20 and B = -7 in Pascal, what is the value of A mod B?

Introduction / Context:
Different languages define integer division and modulo differently for negative operands. Pascal defines mod via the identity a = (a div b) * b + (a mod b), with div truncating toward zero in standard Pascal implementations.

Given Data / Assumptions:

• A = 20, B = -7.
• Pascal's div truncates toward zero (implementation-typical).
• a mod b = a − b * (a div b).

Concept / Approach:
Compute a div b first, then use the defining identity to find a mod b. With truncation toward zero, 20 div −7 = −2 (since −2.857… truncated toward zero is −2). Plugging into the mod identity gives the remainder.

Step-by-Step Solution:

Verification / Alternative check:
Check identity: (−2) * (−7) + 6 = 14 + 6 = 20. The remainder's magnitude is less than |b| = 7, which is consistent.

Why Other Options Are Wrong:

Common Pitfalls:

Final Answer: