The 13 should be 31... then 1+1+1=3 1+1+3=5 1+3+5=9...
18. The pattern is add 5, then subtract 1.
1 5 9 13 17 21
+5
There are 10 possible combinations so 60 possible permutations. The combinations are:(1, 3, 21), (1, 5, 19), (1, 7, 17), (1, 9, 15), (1, 11, 13),(3, 5, 17), (3, 7, 15), (3, 9, 13), (5, 7, 13), (5, 9, 11).
The 13 should be 31... then 1+1+1=3 1+1+3=5 1+3+5=9...
18. The pattern is add 5, then subtract 1.
18. The pattern is 3+1=4, 4+2=6, 6+3=9, 9+4=13, so 13+5=18
Use a text-editor.
13 - 5 + 112 = 9
1 5 9 13 17 21
13...... 9 plus 5 equals 14...... 14 minus 1 equals 13
1, 5, 2, 6, 3, 7, 4, 8, 5, 9, 6, 10, 7, 11, 8, 12, 9, 13, etc.
1, 5, 9, 13....
3 4 6 9 13 18...1....2....3....4......5
To find the pattern, simply look for the difference in the first two numbers, then the following pair of numbers, etc. 2 9 5 13 10 19 17 2 + 7 = 9 9 - 4 = 5 5 + 8 = 13 13 - 3 = 10 10 + 9 = 19 19 - 2 = 17 The pattern is +7, -4, +8, -3, +9, -2...
9 1/16. (1 times 5 is 5, and 13/16 times 5 is 65/16 which is 4 1/16; the 4 adds to the 5 to give 9, and then the 1/16 makes it 9 1/16.)