What is the sum of the first 26 odd numbers?

For example:

1 [one odd number] = 1 = 1²

1 + 3 [Sum of first two odd numbers] = 4 = 2²

1 + 3 + 5 [Sum of first three odd numbers] = 9 = 3²

1 + 3 + 5 + 7 [Sum of first four odd numbers] = 16 = 4² and so on.

Thus, the sum of first 26 odd numbers = 26² = 676.