Mathematics PCT1 revision

Question 1

Why no square number is a prime number?

Answer 1

All square numbers have an odd number of factors. A prime number by definition has exactly 2 factors - 1 and itself. Therefore no prime number is a square and no square number is prime.

Answer 2

1) Find one pair of factors
eg: 120 ( factors 10 , 20 )
2) Find the factors of the factors above ( 10 = 2 x 5 )
3) Each time you write a number that is prime, draw a circle around it. Do not draw any more branches
4) Continue until all branches end in prime number

120 = 2 x 2 x 2 x 3 x 5