It is 37
66
51
51 is half way between 47 and 55.
51-23 = 28
9-2=7, 23-9=14, 51-23=28, 107-51=56. therefore, since the next number in the sequence will be twice the previous difference, it will be 107+112 which is 219
66
51
thirty-seven (37) 51 - 23 = 28 28/2 = 14 51 - 14 = 37 23 + 14 = 37
51 is half way between 47 and 55.
51 = 3 x 17
It is 51
(51+57)/2 = 54
51 is not a prime number: 3x17=51
51 is composite number
23 is the prime number.
An atom it the atomic number 23 has 23 protons.
51-23 = 28