Question

Which of the following equals 3²?

Options

• 1 + 3 = 4

• 1 + 3 + 5 = 9

• 1 + 3 + 5 + 7 = 16

• 1 + 3 + 5 + 7 + 9 = 25

Answer 1

+ 3 + 5 = 9

Explanation:

The sum of the first n odd numbers equals n². For n = 3, we sum the first 3 odd numbers (1, 3, 5) to get 9 = 3².