A prime number has exactly two factors, itself and one. The first ten prime numbers are \({2}\), \({3}\), \({5}\), \({7}\), \({11}\), \({13}\), \({17}\), \({19 ...

45 = 5 \times 9\) and so is not prime. 43 is prime as the only factors of 43 are 1 and 43. The first square number is 1 because \(1 \times 1 = 1\). The second square number is 4 because \(2 \times ...