Solution:

143547

Solution:

3

Explanation:
1 + 2 + 3 + 4 + 5 => 15 => 5 - 1 =>4
4 + 5 + 6 + 7 + 8 => 30 => 3 - 0 =>3
6 + 7 + 8 + 9 + 11 => 41 => 4- 1 =>3

Solution:

7 + 8 = 15 and 15 - 9 = 6
6 + 9 = 15 and 15 - 4 = 11

Therefore, (89)^2 will be:
8 + 9 = 17 and 17 - 2 = 15

Solution:

5

(8+7) * 5 => 75

Solution:

240

40 { diff 20 + 12 =>32 add to it}
72 { diff 32 + 12 =>44 add to it}
116 { diff 44 + 12 =>56 add to it}
172 { diff 56 + 12 =>68 add to it}
240

Solution:

N for Nine

Solution:

Each word rhymes with its numeric position in the list. (e.g. 'gun' rhymes with 'one'
etc.)

Solution:

21, 28.

They are the numbers that either contain the digit 7 or are divisible by 7.

Solution:

60

Explanation:
1 + 5 = 12
But it can be true only if we multiply both digits with 2 and then add:
1*2 + 5*2 = 12

2 + 10 = 24
But it can be true only if we multiply both digits with 2 and then add:
2*2 + 10*2 = 24

3 + 15 = 36
But it can be true only if we multiply both digits with 2 and then add:
3*2 + 15*2 = 36

Similarly,
5 + 25 can be true only if we multiply both digits with 2 and then add:
=> 5*2 + 25*2 = 60

Therefore, the missing number is 60.

Solution:

South

The series: south, east, north, south, west, east spirals clockwise from the top left-hand corner.