Find the unit digit of (365 × 659 × 771).

Given data & approach

• Unit digit of a product depends only on unit digits of factors.

Step-by-step calculation

Units(365) = 5; Units(659) = 9; Units(771) = 1Compute: (5 × 9) = 45 ⇒ units 5Then 5 × 1 ⇒ units 5

Verification

Any number ending in 5 times any odd number ends in 5; multiplying by 1 keeps the unit digit unchanged.

Common pitfalls

• Multiplying full numbers unnecessarily; only unit digits matter.

Final Answer

5