Question

$35^2 =$

• A. 625
• B. 925
• C. 1225
• D. 1025

Answer 1

Answer:

C. 1225

• To calculate the square of a number ending in 5, a simple shortcut exists: (10n + 5)^2 = 100n(n + 1) + 25.
• For 35^2, here n = 3.
• Step 1: Multiply the tens digit by the next consecutive integer: 3 × (3 + 1) = 3 × 4 = 12.
• Step 2: Append 25 to the result of Step 1: 1225.
• Alternatively, using the algebraic identity (a + b)^2 = a^2 + 2ab + b^2, where a=30 and b=5:
• (30 + 5)^2 = 30^2 + 2(30)(5) + 5^2.
• 900 + 300 + 25 = 1225.
• Memorizing squares of numbers up to 50 is highly beneficial for competitive exams to save time on arithmetic-heavy sections.