Solution:

8

Solution:

125874 => 251748

251748 is twice the 125874 and have same digits 1,2,4,5,7 & 8

Solution:

3

Solution:

10968

Water image is 89601

Solution:

117(1+3+5,3+4)

Solution:

12

Solution:

1st fish tank-> 5

2nd fish tank-> 7

Solution:

444 + 444 + 44 + 44 + 4 + 4 + 4 + 4 + 4 + 4 = 1000

Solution:

54
x3
===
162

Solution:

There are 5 Insect-A, 7 Insect-B & 6 Insect-C.

Let 'A' be the number of Insect-A, 'B' be number of Insect-B and 'C' be number of Insect-C.
A+B+C = 18
8A+6B+6C = 118
2B+C = 20
Solving this, A=5, B=7, C=6