Perform the following operations: integer subtraction, simplifying expressions with double negatives, and comparing integers.

First integer $= 6$
Second integer $= 18$

The result is $\boxed{12}$.

b) -3, 6

First integer $= -3$
Second integer $= 6$

The result is $\boxed{9}$.

5. Find the value of:

a) $-37 - (-15) - 2$

The value is $\boxed{-24}$.

b) $16 - [14 - (-2)]$

The value is $\boxed{0}$.

6. Using $>, <$ or $=$, fill in the boxes to make each statement true.

a) $(-1) + (-5) \Box (-7) - (-5)$

The completed statement is $\boxed{(-1) + (-5) < (-7) - (-5)}$.

c) $6 - (-2) + 5 \Box -1 - (-2) - 3$

The completed statement is $\boxed{6 - (-2) + 5 > -1 - (-2) - 3}$.

7. Use commutative and associative property of addition.

c) $43 + 21 + 79 =$

The sum is $\boxed{143}$.

8. Verify:

a) $[(-18) + 4] + 6 = (-18) + (6 + 4)$

The statement is $\boxed{\text{Verified}}$.

c) $(11 + 3) + (-9) = 11 + [3 + (-9)]$

The statement is $\boxed{\text{Verified}}$.