17 cause it is the next prime number
hello
18. 3+1=4, 4+2=6, 6+3=9, 9+4=13, 13+5=18.
13/20 - 3/5 = 13/20 - 12/20 = 1/20
Answer = 21 The next number is the previous 2 numbers added together
37. The difference between two consecutive numbers goes on increasing. 7-2=5; 13-7=6; 20-13=7; 28-20=8; 37-28=9...and so on.
212.
20
13
20
21
18
37, it is 4+1 from the first number and 4+2 from the second number then 4+3 from third so on....
212
31
13 is one possibility.
1834 (3+1)6 (4+2)9 (6+3)13 (9+4)18 (13+5)...and so on