Find the prime and composite numbers between 10 and 30?

Question

can you give the explannation in detail

Answer 1

A prime number can only be evenly divided by 1 and itself.

 

   number     prime  factors

  ---------     ---------

     10               2·5
     11               11
     12              2²·3

     13              13
     14              2·7
     15             3·5
     16             2⁴
     17             17
     18              2·3²
     19              19
     20             2²·5
     21             3·7
     22            2·11
     23            23
     24            2³·3
     25            5²
     26            2·13
     27            3³
     28            2²·7
     29            29
     30            2·3·5

Answer 2

A composite number is a positive integer that can be formed by multiplying

together two smaller positive integers.

 

Prime numbers are divisible only by 1 and themselves... 3, 5, 7, 11, 13,..

They have no other divisors.

 

10:  composite  10 = 5(2)

11:  prime

12:  composite  12 = 4(3) = 6(2)

13:  prime

14:  composite: 14 = 2(7)

15:  composite: 15 = 5(3)

16:  composite:  16 = 4(4) = 8(2)

17:  prime

18:  composite:  18 = 3(6) = 2(9)

19:  prime

20:  composite:  20 = 2(10) = 4(5)

21:  composite:  21 = 3(7)

22:  composite:  22 = 2(11)

23:  prime

24:  composite:  24 = 2(12) = 3(8) = 4(6)

25:  composite:  25 = 5(5)

26:  composite:  26 = 2(13)

27:  composite:  27 = 3(9)

28:  composite:  28 = 4(7) = 2(14)

29:  prime

30:  composite:  30 = 2(15) = 3(10) = 5(6) 

 

Any questions?