Answer
18) $51
19) $24
20) Carla's account.
Step-by-step 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Positive sign values means deposit while the negative values means money been withdrawn from the account.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Positive sign values means money deposited while the negative values means money been withdrawn from the account.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.