Can anyone confirmed and explained 18/19/20

Answer

18) $51

19)  $24

20) Carla's account.

Explanation

18)

Positive sign values means deposit while the negative values means money been withdrawn from the account.

$100 - $18 + $22 - $53 = $51

19)

Positive sign values means money deposited while the negative values means money been withdrawn from the account.

$45 - $17 - $22 + $18 = $24

20)

To get the person with the most deduction, you should add the negative values in the table then compare.

Carla ⇒ -18 + -53 = $-71

Leta ⇒ -17+ -22 = $-39

From here we can see that the account with greatest decrease is Carla's account.