5-6

Do you mean:

• the arithmetic 5 − 6, or
• problems 5–6 in a worksheet, or
• something else (like an interval [5,6])?

If you mean 5 − 6, the answer is -1.

If you want step-by-step subtraction with negative results: 5 − 6 = -(6 − 5) = -1.

Tell me the exact context (topic, worksheet, or subject), and I can tailor practice or explanations.