The Number 28 Trivia Quiz

Answer: 2x2x7

The prime factorization of a number tells what prime numbers multiply to that number. 2x2x5 is 20, 2x3x5 is 30, and 2x3x7 is 42.

Answer: It's the sum of integers from 1 to 7

Each triangular number is the sum of all the integers between 1 and another positive integer. The list of triangular numbers begins with 1, 3, 6, 10, 15, 21, 28, 36, 45, and 55.

Answer: True

28 is a perfect number because its factors (except for itself) are 1, 2, 4, 7, and 14, and they add up to 28, the number itself.

Answer: 27 and 1

The first numbers that are a sum of any two cubes are 1, 2, 8, 9, 16, 27, 28, 35, and 56. This assumes that 0 is a cube because it is 0^3.

Answer: 11100

"11100" means 16+8+4. "11111" means 16+8+4+2+1. "10101" means 16+4+1. So, the incorrect choices were 27 (11011), 24 (11000), and 21 (10110).

Answer: False

The Fibonacci sequence starts with 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. You add the last two numbers to get to the current one. The sequence goes from 21 (8+13) to 34 (13+21), skipping over 28.

Answer: 784

28 cubed is 21952. 28 to the fourth power is 614656.

Answer: 1c

Hexadecimal is base 16. It uses 0 through 9 and the letters a through f as digits. A is 10, b is 11, c is 12, d is 13, e is 14, and f is 15. Instead of there being a tens place and a ones place, there is a sixteens place and a ones place. So "1c" means 16 plus 12. "2a" would be 32 plus 10, which is 42.

Answer: 6

Its six factors are 1, 2, 4, 7, 14, and 28. Only a square number can have an odd number of unique factors.

Answer: 196

196 is 28 times 7, and is also equal to 14 squared.